Alkene Syn Dihydroxylation with Malonoyl Peroxides
摘要:
Cyclopropyl malonoyl peroxide (1), which can be prepared in a single step from the commercially available diacid, is an effective reagent for the dihydroxylation of alkenes. Reaction of 1 with an alkene in the presence of 1 equiv of water at 40 degrees C followed by alkaline hydrolysis leads to the corresponding diol (40-93%). With 1,2-disubstituted alkenes, the reaction proceeds with syn selectivity (3:1 to > 50:1). A mechanism consistent with the experimental findings that is supported by oxygen-labeling studies is proposed.
Metal-Free Dihydroxylation of Alkenes using Cyclobutane Malonoyl Peroxide
作者:Kevin M. Jones、Nicholas C. O. Tomkinson
DOI:10.1021/jo202084w
日期:2012.1.20
Cyclobutane malonoyl peroxide (7), prepared in a single step from the commercially available diacid 6, is an effective reagent for the dihydroxylation of alkenes. Reaction of a chloroform solution of 7 with an alkene in the presence of I equiv of water at 40 degrees C followed by alkaline hydrolysis leads to the corresponding diol (30-84%). With 1,2-disubstituted alkenes, the reaction proceeds with syn-selectivity (3:1 -> 50:1). A mechanism consistent with experimental findings is proposed, which is supported by deuterium and oxygen labeling studies and explains the stereoselectivity observed. Alternative reaction pathways that are dependent on the structure of the starting alkene are also described leading to the synthesis of allylic alcohols and gamma-lactones.