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.