Stereoselective Synthesis of<i>syn</i>-Configured α-Allenols by Rhodium-Catalyzed Reaction of Alkynyl Oxiranes with Arylboronic Acids
作者:Tomoya Miura、Masahiko Shimada、Paula de Mendoza、Carl Deutsch、Norbert Krause、Masahiro Murakami
DOI:10.1021/jo900987w
日期:2009.8.21
A rhodium-catalyzedreaction of alkynyloxiranes with arylboronicacids affords syn-configured α-allenols with high diastereoselectivity. The reaction is initiated by addition of an arylrhodium(I) species onto the alkyne moiety of the alkynyloxirane. The resulting alkenylrhodium(I) intermediate undergoes β-oxygen elimination to open the oxirane ring in a syn-selective fashion. Protonolysis of the
Synthesis of (+)- and (-)-Gossonorol and Cyclisation to Boivinianin B
作者:Keren Abecassis、Susan E. Gibson
DOI:10.1002/ejoc.201000391
日期:2010.5
The first enantioselective synthesis of gossonorol has been achieved in good overall yield and excellent enantioselectivity, demonstrating the utility of a novel approach to enantiopure tertiary benzylic alcohols. Epoxidation of enantiopure gossonorol followed by acid-catalysed cyclisation gave a diastereoisomeric mixture of boivinianinB,typical of the diastereoisomeric mixtures of this compound found
第一个对映选择性合成的 gossonorol 已经以良好的总收率和优异的对映选择性实现,证明了一种新方法对对映纯叔苄醇的效用。对映体纯 gossonorol 环氧化,然后酸催化环化得到 boivinianin B 的非对映异构混合物,这是自然界中发现的这种化合物的典型非对映异构混合物。非对映异构体的分离和对映体纯度的测定表明,在环氧化/环化反应过程中,gossonorol 的苯甲醇的立体化学完整性得到了保留。