Crossed aldol reaction using cross-linked polymer-bound lithium dialkylamide
摘要:
Cross-linked polymer-bound lithium dialkylamides were employed in crossed aldol reaction of various carbonyl compounds with aldehydes to afford the corresponding beta-hydroxycarbonyl compounds. The introduction of spacer chains to the polymer-bound lithium dialkylamide between the base moiety and the polystyrene backbone effectively enhanced yields of the desired aldol adducts. Sometimes better yields were obtained by using the polymer-bound reagent having an appropriate spacer-chain with those obtained using lithium diisopropylamide under homogeneous conditions. Repeated use of these polymeric reagents was demonstrated with no loss of efficiency. (C) 2004 Elsevier Ltd. All rights reserved.
On the use of E-1-methoxymethoxybut-2-enyl(tri-n-butyl)stannane as a threo-selective, homo-enolate equivalent
作者:Andrew J. Pratt、Eric J. Thomas
DOI:10.1039/c39820001115
日期:——
(E)-1-Methoxymethoxybut-2-enyl(tri-n-butyl)stannane, readily available by addition of tri-n-butylstannyllithium to crotonaldehyde, and protection of the alcohol so formed using chloromethyl methyl ether, reacts on heating with aromatic and aliphatic aldehydes to give threo-4,5-disubstituted butyrolactones.