Enantioselective, Palladium-Catalyzed α-Arylation of <i>N</i>-Boc Pyrrolidine: <i>In Situ</i> React IR Spectroscopic Monitoring, Scope, and Synthetic Applications
作者:Graeme Barker、Julia L. McGrath、Artis Klapars、Darren Stead、George Zhou、Kevin R. Campos、Peter O’Brien
DOI:10.1021/jo2011347
日期:2011.8.5
the process; use of (−)-sparteine and the (+)-sparteine surrogate to access products with opposite configuration; development of a catalyticasymmetric lithiation–Negishi coupling reaction; extension to a wide range of heteroaromatic bromides; total synthesis of (R)-crispine A, (S)-nicotine and (S)-SIB-1508Y via short synthetic routes; and examples of α-vinylation of N-Boc pyrrolidine using vinyl bromides
Enantioselective Radical Cyclization for Construction of 5-Membered Ring Structures by Metalloradical C–H Alkylation
作者:Yong Wang、Xin Wen、Xin Cui、X. Peter Zhang
DOI:10.1021/jacs.8b01662
日期:2018.4.11
use of unsaturated substrates. Guided by the concept of metalloradicalcatalysis, a different mode of radical cyclization that can employ saturated C-H substrates is demonstrated through the development of a Co(II)-based system for catalytic activation of aliphatic diazo compounds for enantioselective radical alkylation of various C(sp3)-H bonds. It allows for efficient construction of chiral pyrrolidines
自由基环化代表了构建环状结构的强大策略。传统的自由基环化以自由基加成为关键步骤,需要使用不饱和底物。在金属自由基催化概念的指导下,通过开发基于Co(II)的系统,展示了一种可以使用饱和CH底物的不同自由基环化模式,该系统用于催化活化脂肪族重氮化合物,以实现各种C(sp3)的对映选择性自由基烷基化)-H键。它可以有效构建手性吡咯烷和其他有价值的五元环状化合物。这种自由基环化的替代策略提供了一种新的逆合成范例,通过 CH 和 C=O 元素的结合形成 CC 键,从容易获得的开链醛制备五元环状分子。