Asymmetric hydrogenation of prochiral carboxylic acids and functionalized carbonyl compounds catalysed by ruthenium(II)-binap complexes with aryl nitriles (binap = (R)- or (S)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl)
Complexes RuCl2(ArCN)2(binap), II (binap = (R)- or (S)-2,2′-bis(diphenylphosphino)- 1,1′-binaphthyl; ArCN = benzonitrile, a; 2-furancarbonitrile, b; pentafluorobenzonitrile, c) were prepared, and their solution properties were investigated by 31P NMR measurements. The catalytic activities and enantioselectivities for IIa–c catalysedhydrogenation of some prochiral acids were very similar to those provided
Asymmetric synthesis of (R)- and (S)-4-(substituted benzyl)dihydrofuran-2(3H)-ones: an application of the ruthenium-binap complex-catalysed asymmetric hydrogenation of alkylidenesuccinic acids
A concise synthesis of (S)- or (R)-4-(substituted benzyl)dihydrofuran-2(3H)-ones (1) with high enantiomeric purity is presented. (S)- or (R)-(Substituted benzyl)succinic acids (6) 97% enantiomeric excess) were first prepared by Ru2Cl4[(R)- or (S)-binap)]2(NEt3) catalysed asymmetrichydrogenation of (substituted benzylidene)succinic acids. The diacids (6) were converted into (R)- or (S)-2-(substituted
Berner; Leonardsen, Justus Liebigs Annalen der Chemie, 1939, vol. 538, p. 27
作者:Berner、Leonardsen
DOI:——
日期:——
Berner; Molland, 1936, vol. 9, p. 20
作者:Berner、Molland
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.