01563nas a2200265 4500008004100000022001400041245014800055210006900203260000900272300001100281490000700292520063500299653001600934653002200950653003100972653001901003653002901022100002201051700002101073700001901094700001901113700001701132700002001149856012801169 2020 eng d a0040-402000aHighly efficient chemoselective N-tert butoxycarbonylation of aliphatic/aromatic/heterocyclic amines using diphenylglycoluril as organocatalyst0 aHighly efficient chemoselective Ntert butoxycarbonylation of ali cJUN  a1312230 v763 a

An efficient approach for the Chemoselective N-tert-butoxycarbonylation of a variety of amines using diphenylglycoluril as organocatalyst has been described. For the first time, a plausible mechanism for the N-tert-butoxycarbonylation has been proposed using density functional theory (DFT) calculations supported by NMR studies. The reusability of the organocatalyst and observation of the desired N-Boc protected amines being formed without the formation of side products like urea, oxazolidinone, isocyanate, and N, N-di-Boc derivatives makes the present protocol desirable. (C) 2020 Elsevier Ltd. All rights reserved.

10aDFT studies10aDiphenylglycouril10aN-tert butoxycarbonylation10aorganocatalyst10aProton shuttle mechanism1 aAwasthi, Amardeep1 aMukherjee, Anagh1 aSingh, Mandeep1 aRathee, Garima1 aVanka, Kumar1 aChandra, Ramesh uhttps://library.ncl.res.in/content/highly-efficient-chemoselective-n-tert-butoxycarbonylation-aliphaticaromaticheterocyclic01154nas a2200193 4500008004100000022001400041245011400055210006900169260000900238300001600247490000700263520045600270100002300726700002100749700002100770700001700791700002500808856012700833 2023 eng d a1477-922600aH-atom site exchange in an iridium trans-dihydrogen/hydride complex, trans-[Ir(H)(?2-H2)(iPr)4(POCOP)(DMAP)]+0 aHatom site exchange in an iridium transdihydrogenhydride complex cOCT  a13858-138630 v523 a

Treatment of trans-[Ir(H)(N)(2)((iPr)4)(POCOP)(DMAP)][BAr4f] (2) with H-2 (1 bar) under ambient conditions (298 K) results in the formation of a trans-[Ir(H)(?(2)-H-2)((iPr)4)(POCOP)(DMAP)][BAr4f] (3) complex. Complex 3 exhibits H-atom site exchange between the bound H-2 and the hydride ligands which are mutually trans to one another. A plausible mechanism of this exchange involves metal-ligand cooperativity as studied by computations.

1 aAgrawal, Nisha, K.1 aGayathridevi, S.1 aDash, Soumya, R.1 aVanka, Kumar1 aJagirdar, Balaji, R. uhttps://library.ncl.res.in/content/h-atom-site-exchange-iridium-trans-dihydrogenhydride-complex-trans-irh2-h2ipr4pocopdmap34843nas a2200181 45000080041000002450146000412100071001872600008002583000012002664900007002785203413300285100002234418700002134440700002334461700001734484700002534501856013534526 2025 eng d00aHeterolytic cleavage of the B–H bond in H3B·L (L = THF, NMe2H) by an electrophilic Ir(iii) pincer complex [Ir(H)(PMe3)(tBu4POCOP)][BAr F4]0 aHeterolytic cleavage of the B–H bond in H3B L L THF NMe2H by an  cNOV a476-4910 v553 a
Six- and five-coordinate iridium complexes, [Ir(H)Cl(PMe3)(tBu4POCOP)] (2) (tBu4POCOP = κ3-C6H3-2,6-(OPtBu2)2) and [Ir(H)(PMe3)(tBu4POCOP)][BArF4] (3), respectively, have been synthesized and characterized. The reactivity of the electrophilic 16-electron iridium(III) complex 3 with H2, H3B·THF, H3B·NMe2H, and H3B·NMe3 was investigated. The reaction of complex 3 with H2 resulted in the formation of trans-[Ir(H)(η2-H2)(PMe3)(tBu4POCOP)][BArF4] complex 5. Complex 3 was found to activate the B–H bonds in H3B·THF and H3B·NMe2H (DMAB) in a heterolytic fashion. The reaction of complex 3 with H3B·THF at 298 K afforded trans-[Ir(H)2PMe3(tBu4POCOP)] complex 6 and a boronium compound, [H2B(THF)2][BArF4]. Monitoring the reaction from 179 to 298 K by NMR spectroscopy revealed the formation of a σ-borane intermediate, trans-[Ir(H)(η1-HBH2·THF)PMe3(tBu4POCOP)][BArF4] (3a-Int), en route to the final products observed at 298 K. The formation of this intermediate species was also investigated by density functional theory (DFT) calculations. The reaction of complex 3 with H3B·NMe2H at 298 K yielded a mixture of complexes 3 and 5 and a cyclic diborazane [H2BNMe2]2. The reaction was found to proceed via intermediates, a σ-borane complex, trans-[Ir(H)(η1-HBH2·NMe2H)PMe3(tBu4POCOP)][BArF4] (3b), complex 6, [(NHMe2)2BH2][BArF4], and H2B[double bond, length as m-dash]NMe2. Complex 3 exhibited no reactivity with H3B·NMe3.

 

1 aPradhan, Mitarani1 aSurati, Zeel, Y.1 aPal, Apurba, Kumar1 aVanka, Kumar1 aJagirdar, Balaji, R. uhttps://library.ncl.res.in/content/heterolytic-cleavage-b%E2%80%93h-bond-h3b%C2%B7l-l-thf-nme2h-electrophilic-iriii-pincer-complex01411nas a2200217 4500008004100000022001400041245009500055210006900150260000800219300001400227490000700241520068000248100002300928700002400951700002700975700001501002700001901017700001701036700001901053856012101072 2025 eng d a0276-733300aHypersilylsilylene-supported Ni(0) toluene and Ni(II) complexes with catalytic application0 aHypersilylsilylenesupported Ni0 toluene and NiII complexes with  cNOV a2646-26530 v443 a

The reaction of Ni(COD)2 with [PhC(NtBu)2SiSi(SiMe3)3] (1) in toluene results in the formation of an 18-electron silylene-Ni(0) toluene complex (2). The analogous reaction with 1,3-DFB instead of toluene affords the C-H activation followed by ring walking leading to the allylic cyclooctene adduct, the (eta 3-C8H13)Ni(II) complex (3). DFT calculations were carried out to elucidate the mechanism as well as to gain insight into why 1,3-DFB undergoes C-H bond activation instead of C-F bond activation. The use of NiCl2DME permits access to 16-electron (tetrylene)2NiCl2 (Si(4) and Ge(5)) species, and 4 was later used as a catalyst for the C-N coupling reaction.

1 aAjithkumar, V., S.1 aBisai, Milan, Kumar1 aGhanwat, Pratiksha, B.1 aRaj, Vipin1 aSingh, Geetika1 aVanka, Kumar1 aSen, Sakya, S. uhttps://library.ncl.res.in/content/hypersilylsilylene-supported-ni0-toluene-and-niii-complexes-catalytic-application