Sesquiterpene lactones are natural stereochemically pure compounds, which show a number of biological activities. In order to study the reactivity of sesquiterpene lactones in biological systems, we describe herein the asymmetric synthesis of a simple model, the α-methylene-hexahydrobenzofuranone 1, which includes the α-methylene-γ-butyrolactone moiety and presents all the different possible ring junctions
Asymmetric Catalysis by Vitamin B12: The isomerization of achiral cyclopropanes to optically active olefins
作者:Thomas Troxler、Rolf Scheffold
DOI:10.1002/hlca.19940770502
日期:1994.8.10
Achiral spiroactivated cyclopropanes are isomerized to opticallyactive (R)-(cycloalk-2-enyl)-Meldrum's acids ( = (R)-5-(cycloalk-2-enyl)-2,2-dimethyl-1,3-dioxane-4,6-diones) in high yield and ee's up to 86% by catalytic amounts of cob(I)alamin in polar protic solvents.