Solvent-modulated chemoselective deprotections of trialkylsilyl esters and chemoselective esterifications

A series of trialkylsilyl esters were deprotected or transesterificated into their corresponding carboxylic acids or methyl esters under a catalytic amount of CBr4 in alcohol reaction system. This method enables to desilylate secondary sp(3)-carbon, sp(2)-carbon, sp-carbon and aryl tethered trialkylsilyl esters to carboxylic acids, whereas primary sp(3)-carbon tethered trialkylsilyl esters were further converted into their methyl esters under CBr4/MeOH reaction conditions. The highly chemoselective deprotections can be modulated and achieved by the introduced protecting trialkylsilyl groups and the used alcohols such as MeOH and EtOH under this photochemically-induced reaction conditions. (c) 2005 Elsevier Ltd. All rights reserved.