Calciferol and its relatives. Part XI. Improved routes to (S)-3-hydroxymethyl-4-methylcyclohex-3-en-1-ol

Abstract

Two routes leading to the optically active title compound (9) are described. The first uses, as intermediates, lactonic acids, prepared from enantiomers of 1-methylcyclohex-4-ene-1,2-dicarboxylic acids; the absolute configurations of these enantiomers are thereby established. The second, preferred, route starts from 5-methoxy-2-methyl-benzoic acid and, proceeding via the intermediates (21), (5), and (8) affords the diol (9) in 14% overall yield.