PREPARATION OF CYCLIC ACETALS OF TRANS-4- CHLORO-3-METHYL-BUT-2-EN-1-A1, AND PREPARATION OF TRANS-3-METHYL-BUT-2-ENE-1,4- DIAL-1-MONOACETALS

摘要

A process for the preparation of 6-membered cyclic acetals of trans-4-chloro-3-methyl-but-2-en-1-al by reacting the corresponding acetals of 3-methyl-but-2-en-1-al (prenal), in a halohydrocarbon, with sulfuryl chloride and for their subsequent oxidate on to trans-3-methyl-but-2-ene-1,4-di-al-1-monoacetals (3-methyl-fumarodialdehyde-1-mono-acetals), The trans-3-methyl-but-2-ene-1,4-dial-1-monoacetals are of great importance in terpene syntheses, since they make it possible to carry out successive Wittig reactions giving a very large number of compounts of biological and pharmacological importance.