Crossed Regio‐ and Enantioselective Iron‐Catalyzed [4+2]‐Cycloadditions of Unactivated Dienes
作者:Elena Braconi、Nicolai Cramer
DOI:10.1002/anie.202112148
日期:2022.2.7
An enantioselective iron-catalyzed cross-[4+2]-cycloaddition of unactivated branched and linear dienes is described. The illustrated process provides a very efficient and atom-economic access to chiral 1,3-substituted vinyl-cyclohexenes under very mild reaction conditions. The development of a chiral bis-dihydroisoquinoline ligand class was essential to obtain excellent levels of chemo-, regio- and
Development of Biisoquinoline-Based Chiral Diaminocarbene Ligands: Enantioselective S<sub>N</sub>2‘ Allylic Alkylation Catalyzed by Copper−Carbene Complexes
作者:Hwimin Seo、Dimitri Hirsch-Weil、Khalil A. Abboud、Sukwon Hong
DOI:10.1021/jo702512z
日期:2008.3.1
Chiral biisoquinoline-based diaminocarbene ligands (BIQ) were designed to create a chiral environment extended toward the metal center, which was confirmed by an X-ray structure. The concise ligand synthesis is highlighted by a modified Bischler−Napieralski cyclization of bisamides prepared from readily available chiral phenethylamines, and allows easy variation of the stereodifferentiating groups
设计基于手性双异喹啉的二氨基碳烯配体(BIQ),以创建向金属中心延伸的手性环境,这通过X射线结构得以证实。简明的配体合成是由易得的手性苯乙胺制备的双酰胺的Bischler-Napieralski环的修饰Bischler-Napieralski环合突出显示的,并且可以轻松改变立体分化基团。环己基-BIQ-铜配合物是使用Grignard试剂进行对映选择性S N 2'烯丙基烷基化的有效催化剂,显示出S N 2'区域选择性高于5:1,对映选择性在68-77%ee范围内。
Chiral 1,3,2-Diazaphospholenes as Catalytic Molecular Hydrides for Enantioselective Conjugate Reductions
作者:Solène Miaskiewicz、John H. Reed、Pavel A. Donets、Caio C. Oliveira、Nicolai Cramer
DOI:10.1002/anie.201801300
日期:2018.4.3
of chiral, conformationally restricted methoxy‐1,3,2‐diazaphospholene catalysts is reported. We demonstrate their catalytic potential in asymmetric 1,4‐reductions of α,β‐unsaturated carbonyl derivatives, including enones, acyl pyrroles, and amides, which proceeded in enantioselectivities of up to 95.5:4.5 e.r.
1,2,3,2-二氮杂二膦烯原子具有极化的PH键,并以分子氢化物形式出现。本文报道了一类手性,构象受限的甲氧基-1,3,2-二氮杂磷腈催化剂。我们证明了它们在α,β-不饱和羰基衍生物(包括烯酮,酰基吡咯和酰胺)的不对称1,4-还原反应中的催化潜能,其对映选择性高达95.5:4.5 er