3‐Bromopropenyl Methylcarbonate in Organic Synthesis: A Straightforward Approach to 4,5‐Disubstituted 5‐Vinyl‐1,3‐dioxolan‐2‐ones

Abstract

Abstract The reaction of 3‐bromopropenyl methylcarbonate ( 2 ) with aliphatic or aromatic aldehydes, in the presence of indium metal in N , N ‐dimethylformamide, affords cis and trans 4,5‐disubstituted 5‐vinyl‐1,3‐dioxolan‐2‐ones 4 in very high isolated yields. Reactions may be run by adopting either one‐pot Barbier conditions or a two‐step Grignard protocol. The cis ‐ 4 / trans ‐ 4 ratio is controlled by the nature of the carbonyl compound: saturated aldehydes mainly afford cis ‐ 4 , whereas conjugated aldehydes favor the formation of trans ‐ 4 . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)