Nucleophilic epoxidation of γ-alkoxy dienyl sulfoxide derivatives
作者:Roberto Fernández de la Pradilla、María Victoria Buergo、Carlos Montero、Alma Viso
DOI:10.1016/j.tet.2005.12.024
日期:2006.3
(E,E) and (Z,E) gamma-alkoxy dienyl sulfones undergo nucleophilic epoxidation with remarkable regio- and stereo selectivity to render syn oxiranes in a process mainly controlled by the alkoxy stereocenter. Upon epoxidation gamma-hydroxy dienyl sulfoxides provide sulfinyl and sulfonyl oxiranes along with bis-epoxides formed through a Payne rearrangement that can be prevented by silylation of the OH group. Interestingly, the presence of a gamma-silyloxy group can invert the stereochemical trend of the molecule affording mainly an anti epoxidation process. (c) 2005 Elsevier Ltd. All rights reserved.
Sulfur-Directed Synthesis of Enantiopure Hydroxy 2-Sulfinyl Butadienes
作者:Roberto Fernández de la Pradilla、María Victoria Buergo、María Victoria Martínez、Carlos Montero、Mariola Tortosa、Alma Viso
DOI:10.1021/jo035750g
日期:2004.3.1
The treatment of sulfinyl chlorohydrins with KO-t-Bu in THF generates epoxy vinyl sulfoxides that undergo an efficient base-inducedrearrangement to generate enantiopure hydroxy 2-sulfinyl dienes. This novel process takes place with high chemo- and stereoselectivity. The chirality at sulfur effectively controls the geometry of the trisubstituted alkene.