74975-88-5Relevant academic research and scientific papers
Enantioselective Nickel-Catalyzed Alkyne-Azide Cycloaddition by Dynamic Kinetic Resolution
Liu, En-Chih,Topczewski, Joseph J.
supporting information, p. 5308 - 5313 (2021/05/04)
The triazole heterocycle has been widely adopted as an isostere for the amide bond. Many native amides are α-chiral, being derived from amino acids. This makes α-N-chiral triazoles attractive building blocks. This report describes the first enantioselective triazole synthesis that proceeds via nickel-catalyzed alkyne-azide cycloaddition (NiAAC). This dynamic kinetic resolution is enabled by a spontaneous [3,3]-sigmatropic rearrangement of the allylic azide. The 1,4,5-trisubstituted triazole products, derived from internal alkynes, are complementary to those commonly obtained by the related CuAAC reaction. Initial mechanistic experiments indicate that the NiAAC reaction proceeds through a monometallic Ni complex, which is distinct from the CuAAC manifold.
Enantioselective Copper Catalyzed Alkyne-Azide Cycloaddition by Dynamic Kinetic Resolution
Liu, En-Chih,Topczewski, Joseph J.
, p. 5135 - 5138 (2019/03/29)
The copper(I) catalyzed alkyne-azide cycloaddition (CuAAC), a click reaction, is one of the most powerful catalytic reactions developed during the last two decades. Conducting CuAAC enantioselectively would add a third dimension to this reaction and would
Enantioselective photoredox catalysis enabled by proton-coupled electron transfer: Development of an asymmetric aza-pinacol cyclization
Rono, Lydia J.,Yayla, Hatice G.,Wang, David Y.,Armstrong, Michael F.,Knowles, Robert R.
, p. 17735 - 17738 (2014/01/06)
The first highly enantioselective catalytic protocol for the reductive coupling of ketones and hydrazones is reported. These reactions proceed through neutral ketyl radical intermediates generated via a concerted proton-coupled electron transfer (PCET) event jointly mediated by a chiral phosphoric acid catalyst and the photoredox catalyst Ir(ppy)2(dtbpy)PF6. Remarkably, these neutral ketyl radicals appear to remain H-bonded to the chiral conjugate base of the Bronsted acid during the course of a subsequent C-C bond-forming step, furnishing syn 1,2-amino alcohol derivatives with excellent levels of diastereo- and enantioselectivity. This work provides the first demonstration of the feasibility and potential benefits of concerted PCET activation in asymmetric catalysis.
Achieving vinylic selectivity in Mizoroki-heck reaction of cyclic olefins
Wu, Xiaojin,Lu, Yunpeng,Hirao, Hajime,Zhou, Jianrong
, p. 6014 - 6020 (2013/06/26)
In Heck reactions of cyclic olefins, the products usually have aryl groups that end up at the allylic and/or homoallylic position. We herein report new selectivity that adds aryl groups to the vinylic position. Cyclic olefins of various ring size worked well. The desired isomers were produced by palladium-hydride-catalyzed isomerization of the initial products. Thus, a specific catalyst must be used so that it can perform two jobs under one set of reaction conditions. Copyright
Nickel-catalyzed cross-couplings of cyclohexenyl phosphate and arylboronic acids
Nan, Yang,Yang, Zhen
, p. 3321 - 3324 (2007/10/03)
The Nickel-catalyzed cross-coupling reaction of cyclohexenylphosphate with a variety of arylboronic acids is described here for the first time. This methodology opens the door to other palladium or nickel-catalyzed coupling reactions involving vinyl phosphates.
