Chemistry of Tetrathiomolybdate and Tetraselenotungstate: Applications in Carbohydrate and Peptide Chemistry

Abstract

The reagents, benzyltriethylammonium tetrathiomolybdate, [BnNEt3]2MoS4 1 [1] and tetraethylammonium tetra­selenotungstate [Et4N]2WSe4 2 have been shown to be useful for sulfur and selenium transfer reactions respectively in organic synthesis. Preparation of disulfides from alkyl halides, [2] ring opening of epoxides, [3] tandem sulfur transfer-reduction-Michael addition [4] in one step, reduction of aryl azides to amines [5] and alkyl azides to imines [5] have been reported from our laboratory using the reagent tetrathiomolybdate 1. Tetrathiomolybdate 1 is also used for the selective deprotection of propargyloxycarbonyl (Poc) protective group for amines [6] in peptides and for alcohols [7] in carbohydrate chemistry. Recently, regio­selective reduction of anomeric azides [8] to amines using the reagent 1 has been reported. Reagent 1 has also been used, as a sulfur transfer reagent, for the synthesis of phosphorothioate oligonucleotides. [9] Large quantities of 1 can be prepared from ammonium tetrathiomolybdate and benzyltriethylammonium chloride. [2a]