selectivity in palladium-catalyzedacetoxylation of substituted cycloalkenes and linear alkenes, the influence of added strong acids has been studied. It was found that the product selectivity can be increased in some cases, but also that side reactions lower the total yields when trifluoroacetic or stronger acids are used. The improvement of the selectivity may possibly be due to a change in mechanism for the
A novel synthetic method for γ-butyrolactones is presented. The process involves high regioselectivity to afford γ-lactones. In cases of trichloroacetates of secondary allylic alcohols, high cis-selective cyclization is accomplished.
Ruthenium-catalyzed tandem ring closing metathesis (RCM) – atom transfer radical cyclization (ATRC) sequences
作者:Bernd Schmidt、Michael Pohler
DOI:10.1016/j.jorganchem.2005.06.042
日期:2005.12
alpha-omega-Dienes bearing a pendant trichloroacetoxy group undergo a tandem RCM - radical cycloisomerization sequence leading to bicyclic gamma-butyrolactones, with both steps of the sequence being catalyzed by ruthenium. (c) 2005 Elsevier B.V. All rights reserved.
Transition-metal-catalyzed radical cyclization: copper-catalyzed cyclization of allyl trichloroacetates to trichlorinated .gamma.-lactones