Asymmetric synthesis of 1,3- and 1,3,4-substituted pyrrolidines
摘要:
Diastereoselective alkylation of N-acylnorbornene sultams 2 afforded a variety of enantiomerically pure products 3a-3e. Reduction with LiAlH4 (LAH) followed by ditosylation furnished chiral 1,4-ditosylates 5a-5e which underwent a cyclization reaction with primary amines to afford chiral 1,3- and 1,3;4-substituted pyrrolidines. (C) 2000 Elsevier Science Ltd. All rights reserved.
首次公开了通过非手性稳固的Pd 0配合物和简单的手性胺作为助催化剂的组合,线性醛类的第一个直接的分子间区域特异性和高对映选择性的α-烯丙基烷基化反应。将共催化的不对称化学选择性和区域特异性α-烯丙基烷基化反应与原位还原串联在一起,得到相应的2-烷基醇,其对映体比率很高(er高达98:2; er =对映体比率)。它也是有价值的2-烷基取代的半缩醛,2-烷基-丁烷-1,4-二醇和胺的快速入口。公开了具有生物活性的天然产物(例如,Arundic酸)的简明共催化不对称全合成。
diastereoisomer transformation (CIDT) of naphthoxazines derived from racemic O-protected 2-substituted 4-hydroxybutyraldehydes and enantiopure Betti's base allows the deracemization of the starting aldehydes with ee up to 96%. As an alternative, reduction with lithium aluminum hydride of the diastereoisomerically enriched naphthoxazines leads to enantioenriched primary amines. The utility of the latter strategy
Concise Synthesis of (+)-β-Benzyl γ-Butyrolactones from Butynediol
作者:Stefan Kamlage、Michael Sefkow、Nicole Zimmermann、Martin G. Peter
DOI:10.1055/s-2002-19339
日期:——
The synthesis of optically active β-benzyl-γ-butyrolactones from butynediol via four transition metal catalysed reactions is reported. Key reactions are the hitherto unknown enantioselective hydrogenation of 2-benzyl-2-buten-1,4-diols using Ir(I)-phosphinooxazoline catalysts and the regiocontrolled oxidation of the resulting 2-benzyl-1,4-butanediols to the β-substituted butyro-lactones.
Gagnon, Rene; Grogan, Gideon; Groussain, Esther, Journal of the Chemical Society. Perkin transactions I, 1995, # 20, p. 2527 - 2528
作者:Gagnon, Rene、Grogan, Gideon、Groussain, Esther、Pedragosa-Moreau, Sandrine、Richardson, Paul F.、et al.
DOI:——
日期:——
Diastereoselective conjugate addition of Grignard reagents to a homochiral fumaramide derived from Oppolzer’s sultam
作者:Gary P. Reid、Kieron W. Brear、David J. Robins
DOI:10.1016/j.tetasy.2003.12.010
日期:2004.3
Conjugate addition of Grignard reagents to N,N'-fumaroylbis[(2R)-bornane-10,2-sultam] 1 occurred with moderate to high levels of diastereoselectivity. Diastereomeric excesses were estimated by analysis of the H-1 NMR spectra of the succinamide mixtures and enantiomeric excesses from F-19 NMR spectra of the bis Mosher esters of the diols produced by reductive cleavage of the succinamides. Saponification of the succinamides gave the corresponding (R)-succinic acids with ees up to 92% showing that addition of the Grignard reagents takes place selectively on the re-face of 1. (C) 2003 Elsevier Ltd. All rights reserved.
Direct Regiospecific and Highly Enantioselective Intermolecular α-Allylic Alkylation of Aldehydes by a Combination of Transition-Metal and Chiral Amine Catalysts
The first direct intermolecular regiospecific and highlyenantioselective α‐allylic alkylation of linear aldehydes by a combination of achiral bench‐stable Pd0 complexes and simple chiralamines as co‐catalysts is disclosed. The co‐catalytic asymmetric chemoselective and regiospecific α‐allylic alkylation reaction is linked in tandem with in situ reduction to give the corresponding 2‐alkyl alcohols
首次公开了通过非手性稳固的Pd 0配合物和简单的手性胺作为助催化剂的组合,线性醛类的第一个直接的分子间区域特异性和高对映选择性的α-烯丙基烷基化反应。将共催化的不对称化学选择性和区域特异性α-烯丙基烷基化反应与原位还原串联在一起,得到相应的2-烷基醇,其对映体比率很高(er高达98:2; er =对映体比率)。它也是有价值的2-烷基取代的半缩醛,2-烷基-丁烷-1,4-二醇和胺的快速入口。公开了具有生物活性的天然产物(例如,Arundic酸)的简明共催化不对称全合成。