EFFICIENT SYNTHESIS OF PHOTOLABILE ALKOXY BENZOIN PROTECTING GROUPS

An effective implementation of the Corey-Seebach dithiane addition for the synthesis of photolabile alkoxy benzoin adducts is reported. The method allows for the facile synthesis of photolabile 3',5'-dimethoxyb enzoin protected compounds in near quantitative yield and is general i n that it can be used for the synthesis of both symmetrical and unsymm etrical benzoins. Importantly, the dithiane intermediate reported is a versatile starting material for the synthesis of many photolabile com pounds and should serve as a useful protecting group in complex synthe tic schemes requiring multiple orthogonal protecting groups.