Process for the preparation of carboxylic acid esters of .beta.-formyl-crotyl alcohol by an allyl rearrangement

Abstract

In a process for the preparation of a carboxylic acid ester of .beta.-formyl-crotyl alcohol by rearrangement of the corresponding carboxylic acid ester of 2-formyl-2-hydroxy-but-3-ene or of an acetal or acylate thereof in the presence of copper or a copper compound, followed, where relevant, by hydrolytic cleavage of the acetal or acylate, more especially in the preparation of 4,4-dimethoxy-3-methyl-crotyl acetate, the yield is improved by carrying out the rearrangement in the presence of copper (I) chloride as the catalyst and ensuring that low-boiling by-products formed during the rearrangement are removed. The products are of great importance as starting materials for an industrial synthesis of vitamin A and its derivatives.

Dependencies are inferred from the claim text.