A convenient solvent-specific synthesis of 4-[4-acetoxy-3-(3-methylbut-2-enyl)phenyl]butyric acid

Abstract

Three types of reaction, esterification, C-alkenylation, and O-alkenylation, have been observed between the di-anion (4) and 1-bromo-3-methylbut-2-ene (5) in different solvent systems. Our studies of the effect of the medium on the behaviour of the di-anion (4) towards electrophilic attack by the bromo-alkene (5) resulted in the synthesis of analogues (2) and (6d) of a known anti-sickling agent (3) in high yield. The regioselectivity of the alkenylation reactions is rationalised in terms of solvent polarity.