REGIOSELECTIVITY IN THE REDUCTIVE CLEAVAGE OF PYROGALLOL DERIVATIVES - REDUCTIVE ELECTROPHILIC SUBSTITUTION OF ACETALS OF 2,3-DIMETHOXYPHENOL

Acetals of 2,3-dimethoxyphenol were used as the starting materials for the transformation of 1,2,3-trioxygenated benzenes into various 1-oxy genated-2,3-dicarbon-substituted benzenes, via regioselective reductiv e electrophilic substitution of the 2-methoxy group, followed by conve rsion into the corresponding triflates and a Pd-catalysed cross-coupli ng reaction. The regioselectivity of the reductive cleavage is ascribe d to twisting of the leaving methoxy group out of the plane of the aro matic ring by the two ortho substituents. According to th is methodolo gy, a new synthesis of lunularic acid is presented.