SiCl4 is an efficient and selective catalyst for the vinylogous Mannich reaction of linear and cyclic synthetic equivalents of acetoacetate dianion, leading to delta-amino-beta-ketoesters in moderate to high yields and complete gamma-selectivity; anti-diastereoselectivity was observed by using a gamma-methyl-substituted cyclic silyloxydiene. (c) 2007 Elsevier Ltd. All rights reserved.
Scandium(III)‐Zeolites as New Heterogeneous Catalysts for Imino‐Diels–Alder Reactions
作者:Andrea Olmos、Benoit Louis、Patrick Pale
DOI:10.1002/chem.201103624
日期:2012.4.16
demonstrates the first zeolite‐catalyzed synthesis of piperidine derivatives, including peptidomimetics and indoloquinolizidine alkaloids. The approach developed utilizes a highly effective one‐pot reaction cascade, through imine formation and imino‐Diels–Alderreactions, promoted by scandium‐loaded zeolites as a heterogeneouscatalyst. The methodology described benefits from very low catalyst loadings (≤5 mol %