Preparation of 1,2- and 1,4-diols via selective cleavage of C-benzotriazole bonds in reductive lithiations of N-(α-alkoxy-benzyl- and -allyl-)benzotriazoles

Selective cleavage of C-benzotriazole bonds in the presence of CO bonds is reported for the reductive lithiation of N-(α-alkoxybenzyl)benzotriazoles and N-(α-alkoxyallyl)benzotriazoles in a one-step or two-step process. Trapping of the intermediates with carbonyl compounds gave unsymmetrically protected 1,2 or 1,4-diols in moderate yields.