Process for preparing compounds having a 1,5-dimethyl-hexa-1,5-dienylene group by desulphonylation of a corresponding sulphone

摘要

1,5-Dimethyl-hexa-1,5-dienylene compounds, and especially Vitamin A and derivatives thereof, are made by desuphonylating with a basic reagent a sulphone of the formula: <IMAGE> in which the sulphonyl group -SO2R replaces a hydrogen atom on carbon atom (a) or (b), R represents a phenyl or napthyl group, A is 2-(2,6,6-trimethylcyclohex-1-enyl)ethenyl, and Q is -CH2OH or an ether or ester thereof, CHO, or an acetal group.