Cleavage of MEM ethers by tetrahalozincate reagents

Article abstract of DOI:10.1016/S0040-4020(96)00930-1

A modification of the zinc halide-mediated removal of the MEM group is described. By the expedient of adding two molar equivalents of ethereal hydrogen chloride or of lithium halide, the method is extended to substrates which otherwise chelate the zinc reagent without undergoing deprotection. The compatibility of the resulting reagent Systems with other functional groups is demonstrated, and examples are presented where deprotection of mono-MEM-protected 1,2- and 1,3-diols can be carried out, avoiding the cyclisation which occurs normally.