A highly chemo- and enantioselectiveorganocatalyticcyclopropanation of α,β-unsaturated aldehydes with bromomalonate and 2-bromoacetoacetate esters is presented. The reaction is catalyzed by chiral amines and gives access to 2-formylcyclopropanes in high yields and up to 99 % ee.
N-Heterocyclic Carbene-Catalyzed Domino Ring-Opening/Redox Amidation/Cyclization Reactions of Formylcyclopropane 1,1-Diesters: Direct Construction of a 6−5−6 Tricyclic Hydropyrido[1,2-<i>a</i>]indole Skeleton
作者:Ding Du、Linxia Li、Zhongwen Wang
DOI:10.1021/jo900650h
日期:2009.6.5
Catalyzed by N-heterocycliccarbenes (NHCs), domino ring-opening/redox amidation/cyclization reactions of the readily available formylcyclopropane1,1-diesters with 2-chloro-1H-indole-3-carboaldehydes were reported. This methodology provides an efficient and direct construction of a 6−5−6 tricyclic hydropyrido[1,2-a]indole skeleton, which can be potentially applied for the synthesis of several types
据报道,在N-杂环卡宾(NHC)的催化下,易得的甲酰基环丙烷1,1-二酯与2-氯-1 H-吲哚-3-碳醛的多米诺开环/氧化还原酰胺化/环化反应得到了报道。该方法学提供了一种有效的直接构建6-5-6三环氢吡啶并[1,2- a ]吲哚骨架的方法,可潜在地用于合成几种类型的多环吲哚生物碱。
N-Heterocyclic Carbene Catalyzed Domino Reactions of Formylcyclopropane 1,1-Diesters: Construction of a 6-5-5 Tricyclic Pyrrolo[1,2-a]indole
作者:Linxia Li、Ding Du、Jun Ren、Zhongwen Wang
DOI:10.1002/ejoc.201001364
日期:2011.1
Catalyzed by N-heterocycliccarbenes (NHCs), a domino ring-opening/redox amidation/Knoevenagel condensation of readily available formylcyclopropane1,1-diesters with 1H-indole-2-carbaldehydes is reported. This methodology provides a new and direct method for the construction of a 6-55 tricyclicpyrrolo[1,2-a] indole skeleton.
Palladium-catalyzed enantioselective rearrangement of dienyl cyclopropanes
作者:Qi Xu、Chuan-Jun Lu、Chang-Qiu Guo、Jia Feng、Ren-Rong Liu
DOI:10.1039/d2sc06548g
日期:——
commonly used as dienophiles in a range of cycloaddition reactions. However, VCP rearrangement has not received much attention since its discovery in 1959. In particular, the enantioselectiverearrangement of VCP is synthetically challenging. Herein, we report the first palladium-catalyzed regio- and enantioselectiverearrangement of VCPs (dienyl or trienyl cyclopropanes) for the construction of functionalized