01810nas a2200241 4500008004100000245012900041210006900170260000800239300000900247490000700256520098200263653001101245653003101256653000901287653001901296653001101315100001701326700002101343700003401364700001701398700002301415856013001438 2022 eng d00aSilver dependent enantiodivergent gold(i) catalysed asymmetric intramolecular hydroamination of alkenes: a theoretical study0 aSilver dependent enantiodivergent goldi catalysed asymmetric int cNOV a13920 v123 a

We report a theoretical study of the first silver-dependent enantiodivergent gold-catalysed reaction. The combination of a single chiral binuclear gold(I) chloride complex and silver perchlorate catalyses the asymmetric intramolecular hydroamination of alkenes and affords both enantiomers of the products by applying a simple solvent change from toluene to methanol. A gold-silver chloride adduct that occurs only in methanol appears to control the enantioinversion. If one gold atom coordinates and activates the alkene moiety, the other gold is included in an adduct with silver chloride, which coordinates a methanol solvent molecule and further interacts with the amine function. If the use of toluene implies free anions and affords (S)-enantiomer, methanol allows a proximal interaction with the amine, leads to an opposite stereodifferentiation of the two diastereomeric intermediates during the final protodeauration step and results in the (R)-enantiomer.

10aalkene10aenantiodivergent catalysis10aGold10ahydroamination10aSilver1 aDixit, Ruchi1 aSharma, Himanshu1 aAgbossou-Niedercorn, Francine1 aVanka, Kumar1 aMichon, Christophe uhttps://library.ncl.res.in/content/silver-dependent-enantiodivergent-goldi-catalysed-asymmetric-intramolecular-hydroamination01840nas a2200217 4500008004100000022001400041245012600055210006900181260000800250300001600258490000700274520107300281100002001354700001901374700001901393700002401412700002101436700001701457700001901474856012901493 2022 eng d a0020-166900aTridentate NacNac stabilized tin and nickel complexes: access to a monomeric nickel hydride and its catalytic application0 aTridentate NacNac stabilized tin and nickel complexes access to  cOCT a17370-173770 v613 a

The transmetalation reaction of picolyl-supported tridentate nacnac germylene monochloride [2,6-iPr2-C6H3NC-(Me)CHC(Me)NH(CH2py)]GeCl (1) (py = pyridine) with SnCl2 results in an analogous stannylene chloride (2). The three -coordinated stannylenium cation [{2,6-iPr2-C6H3NC(Me)CHC-(Me)NH(CH2py)}Sn]+ with SnCl3- as a counteranion (3) has been generated through the abstraction of chloride ligand from 2 using an additional equivalent of SnCl2. Instead of forming a donor-acceptor complex, 2 undergoes a facile redox trans-metalation reaction with Ni(COD)2 (COD = cyclooctadiene) and CuCl to afford analogous nickel and copper complexes [2,6-iPr2-C6H3NC(Me)CHC(Me)NH(CH2py)]MCl [M = Ni (4) and Cu (5)]. The reactions of 4 with potassium tri-sec-butylborohydride (commonly known as K-selectride) and AgSbF6 provide access to monomeric Ni(II) hydride, [2,6-iPr2-C6H3NC(Me)CHC(Me)NH(CH2py)]NiH (6) and a Ni(II) cation, [{2,6-iPr2- C6H3NC(Me)CHC(Me)NH(CH2py)}Ni][SbF6] (7), respectively. 6 was found to be an effective catalyst for the hydroboration of amides.

1 aPahar, Sanjukta1 aSharma, Vishal1 aMahata, Biplab1 aGeorge, Christy, P.1 aSharma, Himanshu1 aVanka, Kumar1 aSen, Sakya, S. uhttps://library.ncl.res.in/content/tridentate-nacnac-stabilized-tin-and-nickel-complexes-access-monomeric-nickel-hydride-and01265nas a2200253 4500008004100000022001400041245010900055210006900164260000900233300001500242490000700257520044600264653001200710653002300722653001800745653002400763100001700787700001900804700001800823700002100841700001700862700001900879856011300898 2022 eng d a1867-388000aWell-defined calcium compound catalyzes trimerization of arylisocyanates into 1,3,5-triarylisocyanurates0 aWelldefined calcium compound catalyzes trimerization of arylisoc cJUN  ae2021017880 v143 a

We report the synthesis of a calcium complex (2) bearing a tetradentate monoanionic ligand with a diaminoethane core and phenolate and pyridine peripheral donors. Single crystal X-ray studies on 2 revealed that LiI was also co-crystallized, leading to a four-membered ring with four different elements. 2 was found to be an efficient catalyst for the cyclotrimerization of a variety of aromatic isocyanates under mild conditions.

10acalcium10aCyclotrimerization10aIsocyanurates10aTetradentate ligand1 aKumar, Rohit1 aSharma, Vishal1 aJain, Shailja1 aSharma, Himanshu1 aVanka, Kumar1 aSen, Sakya, S. uhttps://library.ncl.res.in/content/well-defined-calcium-compound-catalyzes-trimerization-arylisocyanates-13501094nas a2200205 4500008004100000022001400041245010400055210006900159260000800228300001400236490000700250520037300257100001900630700002100649700001700670700002600687700002400713700001900737856013200756 2023 eng d a1359-734500aOn the competition between six-membered and five-membered NHC towards alane centered ring expansion0 acompetition between sixmembered and fivemembered NHC towards ala cJUL a8540-85430 v593 a

The combination of 6-SIDipp center dot AlH3 (1) and 5-IDipp resulted in the ring expansion of 6-NHC, while the five-membered NHC remained unchanged, which was subsequently explained by DFT studies. Besides, the substitution chemistry of 1 was also studied with TMSOTf and I-2, which gave rise to the substitution of a hydride by triflate or iodide ligands.

1 aBalayan, Kajal1 aSharma, Himanshu1 aVanka, Kumar1 aRavindranathan, Sapna1 aGonnade, Rajesh, G.1 aSen, Sakya, S. uhttps://library.ncl.res.in/content/competition-between-six-membered-and-five-membered-nhc-towards-alane-centered-ring-expansion02224nas a2200253 4500008004100000022001400041245010100055210006900156260000800225300001100233490000800244520136700252653002401619653003201643653002201675653002901697653002101726653001801747100002101765700001901786700002401805700001701829856012401846 2023 eng d a0022-328X00aComputational insights into the iron-catalyze d magnesium-me diate d hydroformylation of alkynes0 aComputational insights into the ironcatalyze d magnesiumme diate cFEB a1226210 v9863 a

Iron is one of the most abundant transition metals in the earth's crust. It has attracted a lot of attention due to its low toxicity, bio-compatibility, and high natural abundance. Iron-catalyzed hydroamination, hydroalkoxylation, hydrocarboxylation, hydrosilylation, hydroboration, hydrophosphination, hydromagnesiation, and carbonylation reactions have therefore been developed over the past decades. However, despite many experimental and theoretical studies, a complete mechanistic understanding of iron-catalyzed hydrofunctionalisation at the molecular level has not yet been achieved. In this work, through density functional theory (DFT) calculations, we have shown the most feasible path for the hydroformylation of alkynes for an experimentally studied system. We have looked at the iron salt as a precatalyst without any external donor ligand, and the calculations revealed that hydrometalation followed by beta-hydride elimination was favorable over the direct migration of the beta-hydrogen to carbon. Furthermore, our calculations show that the solvent plays an important role in the hydromagnesiation reaction. Furthermore, we have employed an explicit solvent model, where the attachment of one molecule of solvent to the iron center was seen to stabilize the transition states significantly.(c) 2023 Elsevier B.V. All rights reserved.

10aComputational study10aEthylene Assisted Catalysis10aEtMgBr Assistance10aExplicit Role of Solvent10aHydroformylation10aIron Catalyst1 aSharma, Himanshu1 aTewari, Tanuja1 aChikkali, Samir, H.1 aVanka, Kumar uhttps://library.ncl.res.in/content/computational-insights-iron-catalyze-d-magnesium-me-diate-d-hydroformylation-alkynes02779nas a2200217 4500008004100000245010100041210006900142260000900211300001400220490000700234520201600241100002502257700002402282700002102306700002702327700001902354700001702373700001802390700002402408856012902432 2023 eng d00aRivaroxaban eutectics with improved solubility, dissolution rates, bioavailability and stability0 aRivaroxaban eutectics with improved solubility dissolution rates cJUN  a3253-32630 v253 a

Rivaroxaban (RXB) is a direct factor Xa inhibitor used for the treatment of deep vein thrombosis (DVT, a blood clot in the leg) and pulmonary embolism (PE, a blood clot in the lung) and to prevent blood clots in atrial fibrillation following hip or knee surgery. However, RXB suffers from poor solubility that hinders its broader application. Although its cocrystals are reported for solubility enhancement, the methodology used to prepare multi-component crystals is complex. Also, it uses hazardous solvents to develop cocrystals. We have prepared eutectics of RXB with caffeic acid (CAA), coumaric acid (CA), fumaric acid (FA), succinic acid (SA), mandelic acid (MA) and trimesic acid (TA) and analyzed them using hot stage microscopy (HSM), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and fourier transform infrared spectroscopy (FTIR) techniques. The saturation solubility and dissolution rate profiles were also obtained to investigate the effect of eutectics on these parameters. Amongst all the coformers tested, coformers CAA, CA, and FA showed significant enhancement in the solubility of RXB. The powder dissolution rate of the eutectics showed considerable enhancement compared to that of RXB. In vivo pharmacokinetic study was carried out for RXB-CAA, RXB-CA and RXB-FA in rats and compared with RXB, which showed 1.5 and 1.4 times enhancement in relative bioavailability for RXB-CAA and RXB-CA, respectively. Stability studies were carried out as per ICH guidelines for all the eutectics, which revealed excellent stability over six months under accelerated (40 degrees C and 75%) conditions and twelve months under long-term (30 degrees C and 60% RH) conditions. The DFT studies carried out using the B3LYP/TZVP level of theory revealed higher Gibbs free interaction energy (Delta G(int)) for homosynthons (drugMIDLINE HORIZONTAL ELLIPSISdrug and coformerMIDLINE HORIZONTAL ELLIPSIScoformer) than heterosynthons (drugMIDLINE HORIZONTAL ELLIPSIScoformer).

1 aShaligram, Parth, S.1 aGeorge, Christy, P.1 aSharma, Himanshu1 aMahadik, Kakasaheb, R.1 aPatil, Sharvil1 aVanka, Kumar1 aArulmozhi, S.1 aGonnade, Rajesh, G. uhttps://library.ncl.res.in/content/rivaroxaban-eutectics-improved-solubility-dissolution-rates-bioavailability-and-stability01990nas a2200205 4500008004100000022001400041245015200055210007200207260000900279300001600288490000600304520119700310100002501507700002401532700002101556700001701577700002601594700002201620856014201642 2024 eng d a2470-134300aBronsted acid-promoted cyclodimerization of α,β-unsaturated γ-ketoesters: construction of fused pyrano-ketal-lactones and γ-ylidene-butenolides0 aBronsted acidpromoted cyclodimerization of αβunsaturated γketoes cAPR  a19859-198780 v93 a

Unprecedented MsOH-promoted diastereoselective cascade dimerization and intramolecular lactonization of readily accessible alpha,beta-unsaturated gamma-ketoesters are presented. The results obtained in this work, control experiments, and density functional theory (DFT) calculations suggested that the initial enolization and E to Z isomerization/equilibration of olefin (C=C) of substrate alpha,beta-unsaturated gamma-ketoesters give a Z-isomer preferentially over an E-isomer. Subsequently, the Z-isomer undergoes intermolecular annulation with alpha,beta-unsaturated gamma-ketoesters via domino Michael addition/ketalization/lactonization steps to furnish fused tetracyclic pyrano-ketal-lactone. However, the Z-isomer prefers intramolecular trans-esterification in a competing pathway and gives bicyclic gamma-ylidene-butenolide. The key features of this work include simple Br & oslash;nsted acid catalysis, the formation of three bonds, two rings, and three contiguous stereogenic centers in a single step, DFT calculations, and the assignment of relative stereochemistry through X-ray diffraction (XRD) and two-dimensional (2D) nuclear magnetic resonance (NMR) analyses.

1 aVinodkumar, Ramavath1 aNakate, Ashwini, K.1 aSharma, Himanshu1 aVanka, Kumar1 aKrishna, Gamidi, Rama1 aKontham, Ravindar uhttps://library.ncl.res.in/content/bronsted-acid-promoted-cyclodimerization-%CE%B1%CE%B2-unsaturated-%CE%B3-ketoesters-construction-fused01776nas a2200217 4500008004100000022001400041245017200055210007000227260000900297300001400306490000700320520092900327100002701256700003301283700002101316700002401337700001801361700001701379700002501396856013701421 2024 eng d a1477-052000aBrønsted acid- and Ni(ii)-catalyzed C-H oxidation/rearrangement of cyclotriveratrylenes (CTVs) to cyclic and acyclic quinones as potential anti-cancer agents0 aBrønsted acid and Nisciisccatalyzed CH oxidationrearrangement of cJAN  a1038-10460 v223 a

This paper describes a simple and practical protocol for the direct synthesis of acyclic and cyclic quinone derivatives via an acid-promoted nickel(ii)-catalyzed inner rim C-H oxidation of cyclotriveratrylene (CTV) and its analogues. The cyclic quinone derivatives resulted from trimethoxy-cyclotriveratrylene (TCTV) through C-C bond formation via intramolecular ipso substitution followed by subsequent anionic rearrangement containing stereo-vicinal quaternary centers. The DFT calculations strongly support the experimental findings and reveal the role of Bronsted acids in the C-H bond activation of CTV. All the newly synthesized compounds were screened for their in vitro anti-cancer activity using colorimetric SRB assay analysis. Among them, compounds 3a, 3d, 3h, 4a, 4b, 4c and 4e exhibited moderate anticancer activity against A549, HCT-116, PC-3, MDA-MB-231, HEK-293 and SW620 human cancer cell lines.

1 aDarole, Ratanamala, S.1 aChoudhary, Shailendra, Singh1 aSharma, Himanshu1 aMali, Bhupendra, P.1 aGopu, Booblan1 aVanka, Kumar1 aSenthilkumar, Beeran uhttps://library.ncl.res.in/content/br%C3%B8nsted-acid-and-niii-catalyzed-c-h-oxidationrearrangement-cyclotriveratrylenes-ctvs-cyclic01280nas a2200157 4500008004100000022001400041245007600055210007000131260000800201300001400209490000700223520074700230100002100977700001700998856010701015 2024 eng d a0276-733300aIn silico discovery of a neutral 2π aromatic silicon aluminum compound0 aIn silico discovery of a neutral 2π aromatic silicon aluminum co cJUL a1583-15920 v433 a

The recently developed ab initio nanoreactor (AINR) approach to identifying reaction intermediates and pathways without the necessity of experimental input has been employed in the current work to locate new cyclic silicon-based structures that have the potential to display aromaticity. Using this approach, we have identified many cyclic silicon-based molecules that have been experimentally reported over the past three decades. More importantly, the current work showcases an interesting new molecule that has been discovered through this approach: a four-membered cyclic compound of silicon and aluminum that displays significant 2 pi aromaticity and is capable of the activation of important small molecules such as ammonia.

1 aSharma, Himanshu1 aVanka, Kumar uhttps://library.ncl.res.in/content/silico-discovery-neutral-2%CF%80-aromatic-silicon-aluminum-compound02631nas a2200205 4500008004100000022001400041245009200055210006900147260000800216490000700224520194000231100001702171700001902188700001702207700001802224700002102242700001702263700002402280856012102304 2024 eng d a2044-475300aIron-catalyzed (E)-selective hydrosilylation of alkynes: scope and mechanistic insights0 aIroncatalyzed Eselective hydrosilylation of alkynes scope and me cMAY0 v143 a

Iron-catalyzed hydrosilylation of internal alkynes has been rarely reported. Even in these rare cases, additives have been used for the success of the reaction, which often creates a problem for the functional group tolerance of the reaction. Herein, we report an additive-free iron-catalyzed (E)-selective hydrosilylation of internal alkynes in the presence of a phosphine ligand. A low-valent Fe(0) complex [Fe(CO)(3)(BDA)] {[Fe-1]} catalyzed the hydrosilylation of alkynes at 60 to 120 degrees C, exhibited a broad substrate (24 substrates) scope and tolerated different functional groups. The synthetic utility of the reaction was demonstrated by a gram scale experiment, preparing alkenes, and by chemo-selective hydrosilylation. The modus operandi of the reaction has been investigated by i) homogeneity test, ii) radical trapping experiments, iii) X-ray photoelectron spectroscopy, and iv) by preparing a Fe(II) complex as catalyst control. These mechanistic investigations revealed a two-electron pathway for the hydrosilylation of alkynes. In addition, kinetic investigations were undertaken to shed light on the rates of the reaction. Kinetic studies suggest the absence of an induction period, and the reaction is first order with respect to the concentration of iron catalyst [Fe-1] and zeroth order with respect to the substrate (alkyne). The Hammett plot suggests that strongly electron-withdrawing groups on the alkyne favour the hydrosilylation reaction. Meanwhile Eyring analysis suggests that the rate-determining step likely involves an associative pathway. Based on the findings of the mechanistic and kinetic investigation, a plausible Chalk-Harrod-type mechanism is likely to be operative. The proposed mechanism is substantiated by computational investigations, which suggested that the Chalk-Harrod mechanism is kinetically more favored by 15.8 kcal mol(-1) over the modified Chalk-Harrod mechanism.

1 aSen, Anirban1 aTewari, Tanuja1 aKumar, Rohit1 aVinod, C., P.1 aSharma, Himanshu1 aVanka, Kumar1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/iron-catalyzed-e-selective-hydrosilylation-alkynes-scope-and-mechanistic-insights01687nas a2200181 4500008004100000245011000041210006900151260000800220300001400228490000600242520102800248100002301276700002101299700002101320700001701341700001601358856013101374 2024 eng d00aRational monomer design for the synthesis of conjugated polymers by direct heteroarylation polymerization0 aRational monomer design for the synthesis of conjugated polymers cJUL a449–4590 v43 a

This study focuses on the design concepts that contribute to the C–H activation in bithiophene-flanked monomers incorporating naphthalene diimide (NDI), perylene diimide (PDI), and fluorene (FLU) and their polymerization by direct heteroarylation. Density functional theory (DFT) calculations reveal distinct energy requirements for C–H bond abstraction, which is dictated by the electron-withdrawing strength of the central aromatic core flanked by bithiophene. These provide insights into the reactivity of each monomer for C–H bond activation. Proton NMR spectroscopic experimental results confirm the favorable energetic profiles predicted by DFT, with NDI- and PDI-flanked monomers exhibiting lower energy requirements than fluorene-flanked monomers. Successful polymer synthesis is demonstrated for NDI and PDI, while the fluorene-flanked monomer shows challenges due to its higher energy demands.

1 aKakde, Navnath, R.1 aSharma, Himanshu1 aDalvi, Nitin, V.1 aVanka, Kumar1 aAsha, S., K uhttps://library.ncl.res.in/content/rational-monomer-design-synthesis-conjugated-polymers-direct-heteroarylation-polymerization02139nas a2200193 4500008004100000022001400041245008200055210006900137260000800206300001400214490000700228520150100235100002501736700002101761700002701782700001501809700001701824856010401841 2024 eng d a0020-166900aSize matters: computational insights into the crowning of noble gas trioxides0 aSize matters computational insights into the crowning of noble g cFEB a4099-41070 v633 a

In pursuit of enhancing the stability of the highly explosive and shock-sensitive compound XeO3, we performed quantum chemical calculations to investigate its possible complexation with electron-rich crown ethers, including 9-crown-3, 12-crown-4, 15-crown-5, 18-crown-6, and 21-crown-7, as well as their thio analogues. Furthermore, we expanded our study to other noble gas trioxides (NgO(3)), namely, KrO3 and ArO3. The basis set superposition error (BSSE) corrected interaction energies for these adducts range from -13.0 kcal/mol to -48.2 kcal/mol, which is notably high for sigma-hole-mediated noncovalent interactions. The formation of these adducts was observed to be more favorable with the increase in the ring size of the crowns and less favorable while going from XeO3 to ArO3. A comprehensive analysis by various computational tools such as the mapping of the electrostatic potential (ESP), Wiberg bond indices (WBIs), Bader's theory of atoms-in-molecules (AIM), natural bond orbital (NBO) analysis, noncovalent interaction (NCI) plots, and energy decomposition analysis (EDA) revealed that the C-H center dot center dot center dot O interactions, as well as dispersion interactions, play a pivotal role in stabilizing adducts involving larger crowns. A noteworthy outcome of our study is the revelation of a coordination number of 9 for xenon in the complex formed between XeO3 and the thio analogue of 18-crown-6, which is higher than the largest number reported to date.

1 aDash, Soumya, Ranjan1 aSharma, Himanshu1 aTiwari, Mrityunjay, K.1 aGreb, Lutz1 aVanka, Kumar uhttps://library.ncl.res.in/content/size-matters-computational-insights-crowning-noble-gas-trioxides02067nas a2200193 4500008004100000022001400041245014200055210006900197260000800266300001600274490000700290520135000297100001901647700002101666700001701687700002401704700001901728856012601747 2024 eng d a2041-652000aUncovering diverse reactivity of NHCs withdiazoalkane: C-H activation, C=C bond formation,and access to N-heterocyclic methylenehydrazine0 aUncovering diverse reactivity of NHCs withdiazoalkane CH activat cNOV a18387-183940 v153 a

N-heterocyclic carbenes (NHCs) have attracted significant attention due to their strong sigma-donating capabilities, as well as their transition-metal-like reactivity towards small molecules. However, their interaction with diazoalkanes remains understudied. In this manuscript, we explore the reactivity of a series of stable carbenes, encompassing a wide range of electronic properties, with Me3SiCHN2. 5-SIPr activates the C-H bond of Me3SiCHN2, resulting in the formation of a novel diazo derivative (1), while carbenes such as 5-IPr, 6-SIPr, and diamido carbene yield N-heterocyclic methylenehydrazine derivatives (3, 4, and 8). The reaction of Me3SiCHN2 with 5-ItBu unexpectedly leads to the formation of a triazole ring linked with the imidazole moiety via a CC double bond (6) alongside the azine product (7). Substituting the diazoalkane with diazoester consistently yields azine derivatives (9-12 and 14). Only in the case of 5-ItBu, an imidazolium salt with tetrazenide anion (13) was obtained as a side product. The reaction of 4 with HCl resulted in the desilylprotonation to form a salt, 5a, which undergoes deprotonation upon using bases such as Et3N and KHMDS to form N-heterocyclic methylene hydrazine, 5. Theoretical calculations have been conducted to elucidate the diverse mechanisms underlying product formation.

1 aBalayan, Kajal1 aSharma, Himanshu1 aVanka, Kumar1 aGonnade, Rajesh, G.1 aSen, Sakya, S. uhttps://library.ncl.res.in/content/uncovering-diverse-reactivity-nhcs-withdiazoalkane-c-h-activation-cc-bond-formationand00891nas a2200265 4500008004100000022001400041245011500055210007000170260000900240300001600249490000700265653001500272653001700287653001500304653001500319100002500334700001700359700001900376700002100395700001500416700002000431700002000451700001700471856013700488 2024 eng d a1359-734500aUnravelling the prebiotic origins of the simplest α-ketoacids in cometary ices: a computational investigation0 aUnravelling the prebiotic origins of the simplest αketoacids in  cOCT  a11283-112860 v6010aGLYOXYLATE10aHydrocarbons10aMetabolism10aPrecursors1 aDash, Soumya, Ranjan1 aPandya, Rinu1 aSingh, Geetika1 aSharma, Himanshu1 aDas, Tamal1 aHaldar, Hritwik1 aHotha, Srinivas1 aVanka, Kumar uhttps://library.ncl.res.in/content/unravelling-prebiotic-origins-simplest-%CE%B1-ketoacids-cometary-ices-computational-investigation02259nas a2200277 4500008004100000245015100041210006900192260000800261300001600269490000600285520129900291653001801590653002801608653000801636653002001644653003001664653002401694100002001718700001901738700001801757700002101775700001701796700001701813700002001830856013101850 2025 eng d00aBioinspired synthesis of bridged isochromane fused pyrazoles by a silver catalyzed cascade reaction and its application for antibacterial activity0 aBioinspired synthesis of bridged isochromane fused pyrazoles by  cAUG a4184–41950 v53 a

A stereoselective silver catalyzed one pot vinylogous aldol addition followed by a cascade [4+2] cycloaddition reaction of α-arylidene pyrazolinones to in situ generated isochromenylium ions has been developed, which provides an unprecedented bridged [2.2.2] [3.3.1] pentacyclic [5-6-6-6-6] skeleton consisting of an isochroman, chroman, and a pyrazole unit in one molecule with good to high yields as a single diastereomer. This method offers mild reaction conditions, wide substrate compatibility, excellent scalability and easy derivatization. A DFT study was carried out to clarify the reaction mechanism. It was exciting to observe that the unprecedented bridged isochromans synthesized here have shown excellent selectivity toward Gram-positive and Gram-negative bacteria. We demonstrate that while some structures are broad spectrum antibacterial there are two distinct structures that can be explored for selective activity.

10aAntibacterial10aBridged [2.2.2] [3.3.1]10aROS10aStereoselective10aVinylogous aldol addition10a[4+2] cycloaddition1 aSingh, Bhuvnesh1 aTewari, Shreya1 aKaur, Manleen1 aSharma, Himanshu1 aVanka, Kumar1 aSingh, Neetu1 aSingh, Ravi, P. uhttps://library.ncl.res.in/content/bioinspired-synthesis-bridged-isochromane-fused-pyrazoles-silver-catalyzed-cascade-reaction01665nas a2200169 4500008004100000022001400041245013300055210006900188260000900257300001600266490000700282520101400289100002101303700002201324700001701346856013201363 2025 eng d a0022-326300aFrom Delocalization to Disruption: The Role of Aromaticity in N-Heterocyclic Carbenes' Reactions with Diazoalkane and Diazoester0 aFrom Delocalization to Disruption The Role of Aromaticity in NHe cSEP  a12409-124240 v903 a

Aromaticity is a fundamental force shaping molecular stability and reactivity, yet its dynamic role along reaction coordinates remains poorly understood. In this study, we unveil how dynamic changes in aromatic character govern the reactivity of 5-ItBu with diazoalkanes and diazoesters through a multifaceted computational approach. By integrating electronic, magnetic, structural, and energetic aromaticity descriptors, we demonstrate that the retention of aromaticity along the reaction path markedly lowers activation barriers, while its disruption imposes significant energetic penalties. Activation strain model (ASM) and energy decomposition analysis (EDA) further underscore the role of aromatic stabilization in enhancing orbital interactions that drive reactivity. These insights establish a cohesive mechanistic framework, highlighting aromaticity not merely as a static structural feature but as a tunable lever in the design of selective transformations and next-generation catalysts.

1 aSharma, Himanshu1 aFernandez, Israel1 aVanka, Kumar uhttps://library.ncl.res.in/content/delocalization-disruption-role-aromaticity-n-heterocyclic-carbenes-reactions-diazoalkane-and01792nas a2200241 4500008004100000022001400041245009600055210006900151260000800220490000700228520099400235653001901229653002601248653001901274653001701293653001401310100001901324700002401343700002101367700001701388700002401405856012101429 2025 eng d a2193-580700aIron-catalyzed chemoselective reduction of enimines to N-Allylic amines via hydrosilylation0 aIroncatalyzed chemoselective reduction of enimines to NAllylic a cMAY0 v143 a

Chemoselective hydrosilylation of unsaturated imines is challenging as the two double bonds compete for the reaction. Here in, we report an iron-catalyzed chemoselective hydrosilylation of enimines leading to the generation of allyl amines in the presence of phosphine ligand. A low-valent Fe(0) complex [(BDA)Fe(CO)3] catalyzed the hydrosilylation of enimine at room temperature and exhibited broad substrate scope including a variety of enimine (cinnamylimine, allylimine) and ketimine. Mechanistic investigations revealed that the reaction proceeds through an oxidative addition of the silane compound, leading to the formation of an iron hydride intermediate. Subsequently, a two-electron pathway facilitates the hydrosilylation of the enimine substrate. This has been supported by preparing a well-defined Fe(II)-silane complex and using it as a catalyst control. Based on experimental and computational investigations, a plausible Chalk-Harrod-type mechanism is proposed.

10aCinnamyl amine10aImine hydrosilylation10airon catalysis10aIron hydride10aPhosphine1 aTewari, Tanuja1 aShaikh, Maulali, H.1 aSharma, Himanshu1 aVanka, Kumar1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/iron-catalyzed-chemoselective-reduction-enimines-n-allylic-amines-hydrosilylation02261nas a2200241 4500008004100000022001400041245011100055210007000166260000900236490000700245520143100252653001901683653002501702653001501727653002001742653000901762100001901771700001801790700002101808700001701829700002301846856015001869 2025 eng d a0947-653900aPair of dinuclear Fe(II) enantiomers: syntheses and structures of ΛΔ/ΔΛ-Bis(Dihydridoborate) complexes0 aPair of dinuclear FeII enantiomers syntheses and structures of Λ cFEB 0 v313 a

In our effort to establish a direct synthetic approach for bis(dihydridoborate) complexes of first-row transition metals, we have investigated the reactivity of [Cp*Fe(dppe)Cl] (dppe =1,2-bis(diphenylphosphino)ethane) with Na[BH3L] (L =2-mercaptopyridine (mp) and 2-mercaptobenzothiazole (mbz)) that led to the formation of iron(II) dihydridoborate complexes, [Cp*Fe{kappa 3-S,H,H-(H2BH(L))}] 1 a-b (L=mp (1 a) and L=mbz (1 b)). Further, in an attempt to isolate the bis(dihydridoborate) complex of iron by the insertion of borane into the kappa 2-N,S-chelated iron complex, [(dppe)Fe{kappa 2-N,S-(mp)}2] (2), we have isolated and structurally characterized a rare example of dimeric iron bis(dihydridoborate) complex, [Fe{kappa 3-S,H,H-(H2BH(mp))}2]2, Lambda Delta/Delta Lambda-3 as pair of enantiomers. Interestingly, these enantiomers Lambda Delta/Delta Lambda-3 have two trans-[Fe{kappa 3-S,H,H-(H2BH(mp))}2] moieties bridged through sulfur atoms of 2-mercaptopyridinyl ligands, where the iron centres are hepta-coordinated. The natural bond-orbital (NBO) analyses of Lambda Delta-3 and Delta Lambda-3 show considerable electron donation from the filled sigma B-H bonding orbital to vacant dz2 \${{d}_{{z}<\^>{2}}}\$ orbital of iron with a substantial contribution from the hydrogen atoms. The localized orbital bonding analysis (LOBA) method suggests that all the iron centres are in +2 oxidation state.

10aB-H activation10aBis(dihydridoborate)10aEnantiomer10aHeptacoordinate10airon1 aKaur, Urminder1 aGayen, Sourav1 aSharma, Himanshu1 aVanka, Kumar1 aGhosh, Sundargopal uhttps://library.ncl.res.in/content/pair-dinuclear-feii-enantiomers-syntheses-and-structures-%CE%BB%CE%B4%CE%B4%CE%BB-bisdihydridoborate-complexes01079nas a2200205 4500008004100000022001400041245008300055210006900138260000800207300001600215490000700231520039700238100002500635700002200660700002300682700002100705700001700726700001800743856011200761 2025 eng d a1359-734500aSilylene-copper(i) catalysis: regioselective protoboration of terminal alkynes0 aSilylenecopperi catalysis regioselective protoboration of termin cDEC a19652-196550 v613 a

Herein, we report an efficient regioselective protoboration of the terminal alkynes catalyzed by newly synthesized silylene-copper(i)-aryl complexes. This method offers a broad substrate scope, good functional-group compatibility, and a gram-scale synthetic ability. The insight into the mechanistic cycle is also provided with the support of experimental and theoretical studies.

1 aKaulage, Sandeep, H.1 aShah, Brij, Kumar1 aPanday, Rishukumar1 aSharma, Himanshu1 aVanka, Kumar1 aKhan, Shabana uhttps://library.ncl.res.in/content/silylene-copperi-catalysis-regioselective-protoboration-terminal-alkynes01950nas a2200253 4500008004100000022001400041245009600055210006900151260000900220490000700229520108400236653004101320653002501361653001501386653003001401100002501431700002201456700002101478700001901499700001701518700002401535700002201559856011501581 2025 eng d a1861-472800aStudies on the stereoselective synthesis of sacubitril via a chiral amine transfer approach0 aStudies on the stereoselective synthesis of sacubitril via a chi cMAR 0 v203 a

We present a comprehensive account of our efforts directed towards the synthesis of sacubitril, a neprilysin inhibitor used in combination with valsartan and marketed as Entresto (TM). Our initial approach to the formal synthesis of sacubitril employed a chiral pool strategy, utilizing (S)-pyroglutamic acid as a key building block and Cu(I)-mediated Csp2-Csp3 cross-coupling as a key transformation. Further investigations led to the development of chiral amine transfer (CAT) reagents-based stereoselective synthesis. This involved the E-selective construction of gamma-ylidene-butenolide from readily available biphenyl bromide and 4-pentynoic acid, the conversion of this butenolide to its ene-lactam using chiral amine, and substrate-controlled diastereoselective reduction of ene-lactam using Et3SiH or Pd/C, H2 (overall chiral amine transfer) as key transformations. Antipodal lactam intermediates were synthesized using corresponding chiral amines, and the stereochemical outcomes during the ene-lactam reduction with Et3SiH were rationalized by DFT studies.

10aChiral Amine Transfer (CAT) approach10aChiral pool approach10aSacubitril10astereoselective synthesis1 aSadanande, Megha, V.1 aThorat, Sagar, S.1 aSharma, Himanshu1 aSingh, Geetika1 aVanka, Kumar1 aGonnade, Rajesh, G.1 aKontham, Ravindar uhttps://library.ncl.res.in/content/studies-stereoselective-synthesis-sacubitril-chiral-amine-transfer-approach01146nas a2200193 4500008004100000022001400041245011300055210006900168260000800237300001400245490000700259520045800266100001900724700002100743700001700764700002400781700001900805856012800824 2025 eng d a0276-733300aSynthesis of diamido N-heterocyclic imines (DAC = NH) via staudinger or reductive N-N bond cleavage approach0 aSynthesis of diamido Nheterocyclic imines DAC NH via staudinger  cMAY a1129-11330 v443 a

This report communicates the first examples of N-heterocyclic imines based on electrophilic diamido carbenes (DACs). While 2 is prepared by classical Staudinger synthesis, 4 is obtained via an unusual reductive N-N bond cleavage of an azine by HCl. The exocyclic C=N bond lengths in 2 and 4 are substantially shorter than those based on N-heterocyclic carbenes and cyclic (alkyl)(amino)carbene reflecting the electrophilic character of DACs.

1 aBalayan, Kajal1 aSharma, Himanshu1 aVanka, Kumar1 aGonnade, Rajesh, G.1 aSen, Sakya, S. uhttps://library.ncl.res.in/content/synthesis-diamido-n-heterocyclic-imines-dac-nh-staudinger-or-reductive-n-n-bond-cleavage01206nas a2200205 4500008004100000245011000041210006900151260000800220300001400228490000700242520046500249100002400714700002200738700002100760700002500781700002400806700001700830700002400847856012900871 2026 eng d00aSwitchable solid-state emission in GFP chromophore analogue cocrystals via competing AIE and ACQ pathways0 aSwitchable solidstate emission in GFP chromophore analogue cocry cMAR a1775-17800 v283 a

We present a crystal-engineering approach enabling switchable solid-state emission (green -> orange -> quenched) in GFP-chromophore analogue cocrystals. The coformer's electronic and supramolecular effect shifts the photophysical pathway: intramolecular CT in cocrystal-I (green) and cocrystal-III (quenched) and intermolecular CT in cocrystal-II, yielding orange emissions and highlighting cocrystallization's power for tunable luminophores.

1 aMali, Bhupendra, P.1 aDabke, Niteen, B.1 aSharma, Himanshu1 aDash, Soumya, Ranjan1 aManoj, Kochunnoonny1 aVanka, Kumar1 aGonnade, Rajesh, G. uhttps://library.ncl.res.in/content/switchable-solid-state-emission-gfp-chromophore-analogue-cocrystals-competing-aie-and-acq01270nas a2200229 4500008004100000022001400041245006800055210006700123260000800190300001400198490000700212520056400219100001900783700002000802700002100822700002200843700001700865700002400882700001900906700001900925856009600944 2026 eng d a1477-922600aUnveiling the reactivity of N-heterocyclic methylene hydrazines0 aUnveiling the reactivity of Nheterocyclic methylene hydrazines cAPR a5432-54360 v553 a

We present the first reactivity profile of N-heterocyclic methylene hydrazines, revealing distinct competition between steric and electronic control. Reactions with HCl are electronically driven, resulting in protonation at the proximal nitrogen, while the bulky Lewis acid B(C6F5)3 coordinates to the sterically accessible distal nitrogen. Additionally, we demonstrate that these scaffolds undergo spontaneous, base-free HCN elimination with tetracyanoethylene (TCNE) to form highly conjugated molecules with significantly reduced HOMO-LUMO gaps.

1 aBalayan, Kajal1 aBiswas, Arindam1 aSharma, Himanshu1 aTiwari, Prabhakar1 aVanka, Kumar1 aGonnade, Rajesh, G.1 aRath, Arup, K.1 aSen, Sakya, S. uhttps://library.ncl.res.in/content/unveiling-reactivity-n-heterocyclic-methylene-hydrazines