METHOD OF MAKING 2,7-DIMETHYL-2,4,6-OCTATRIENEDIAL, A KEY INTERMEDIATE IN THE COMMERCIAL SYNTHESES OF VARIOUS CAROTENOIDS

摘要

A procedure for forming methylmalonaldehyde from propionaldehyde, an alkyl formate and a sodium alkoxide, utilizing a crossed-Claisen condensation is disclosed. The procedure avoids the formation of aldol condensation products. Also disclosed are processes for preparing 3-alkoxy-2-methylpropenals such as 2-methyl-3-(2-methyl-2-propenoxy)propenal from methylmalonaldehyde. The latter products are useful in the synthesis of carotenoids.