@article {48405, title = {Silver dependent enantiodivergent gold(i) catalysed asymmetric intramolecular hydroamination of alkenes: a theoretical study}, journal = {Catalysts}, volume = {12}, year = {2022}, month = {NOV}, pages = {1392}, type = {Article}, abstract = {

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.

}, keywords = {alkene, enantiodivergent catalysis, Gold, hydroamination, Silver}, doi = {10.3390/catal12111392}, author = {Dixit, Ruchi and Sharma, Himanshu and Agbossou-Niedercorn, Francine and Vanka, Kumar and Michon, Christophe} } @article {49089, title = {Size matters: computational insights into the crowning of noble gas trioxides}, journal = {Inorganic Chemistry}, volume = {63}, year = {2024}, month = {FEB}, pages = {4099-4107}, type = {Article}, abstract = {

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{\textquoteright}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.

}, issn = {0020-1669}, doi = {10.1021/acs.inorgchem.3c03782}, author = {Dash, Soumya Ranjan and Sharma, Himanshu and Tiwari, Mrityunjay K. and Greb, Lutz and Vanka, Kumar} } @article {49507, title = {Studies on the stereoselective synthesis of sacubitril via a chiral amine transfer approach}, journal = {Chemistry-An Asian Journal}, volume = {20}, year = {2025}, month = {MAR }, type = {Article}, abstract = {

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.

}, keywords = {Chiral Amine Transfer (CAT) approach, Chiral pool approach, Sacubitril, stereoselective synthesis}, issn = {1861-4728}, doi = {10.1002/asia.202401223}, author = {Sadanande, Megha V. and Thorat, Sagar S. and Sharma, Himanshu and Singh, Geetika and Vanka, Kumar and Gonnade, Rajesh G. and Kontham, Ravindar} } @article {49683, title = {Synthesis of diamido N-heterocyclic imines (DAC = NH) via staudinger or reductive N-N bond cleavage approach}, journal = {Organometallics}, volume = {44}, year = {2025}, month = {MAY}, pages = {1129-1133}, type = {Article}, abstract = {

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.

}, issn = {0276-7333}, doi = {10.1021/acs.organomet.5c00120}, author = {Balayan, Kajal and Sharma, Himanshu and Vanka, Kumar and Gonnade, Rajesh G. and Sen, Sakya S.} }