Derivatives of orthoacids. IV. Acid-catalysed thermal eliminations and baseinduced eliminations of some 2-Ethoxy-1,3-dioxolans

Abstract

A series of phenyl substituted 2-ethoxy-1,3-dioxolans (orthoformates) has been prepared and their stereochemistry assigned. When heated in the presence of a carboxylic acid they underwent a stereospecific cis elimination to form the corresponding olefins, carbon dioxide, and ethanol. Provided that one 4 or 5 position in these dioxolans was unsubstituted, they reacted with butyllithium through elimination of the elements of ethyl formate and the formation of a carbonyl compound. The eliminated portion was always converted by the butyllithium into nonan-5-ol. A simple preparative method for cis-stilbene is described.