Desulfurization of aromatic polysulfides with triphenylphosphine

Abstract

The room temperature reaction of bis(4-methylbenzene) di- (3), tri- (4) and tetrasulfide (5) with triphenylphosphine has been followed by ¹H NMR. Mechanistic aspects of the cleavage of 3 and the desulfurization of 4 and 5, with concomitant formation of triphenylphosphine sulfide, are discussed. While tetrasulfide 5 is desulfurized over 10× faster than trisulfide 4, preliminary experiments indicate that 5 is not sufficiently reactive to efficiently transfer a sulfur atom to oligodeoxyribonucleotides.

Keywords:

• Disulfides
• Trisulfides
• Tetrasulfides
• Desulfurization
• Triphenylphosphine

Acknowledgments

We thank NSERC for support. EZ-C thanks FCAR for a personal scholarship. We are especially grateful to Dr R. Bruce Lennox (McGill University) for helpful discussions regarding the kinetics analysis. Helpful discussions with Dr Harry R. Hudson (University of North London) regarding ³¹P NMR detection of intermediates are also acknowledged. We also thank Dr Ekaterina Viazovkina for preliminary testing of 5 with oligodeoxyribonucleotides.