Tetrahedron letters

Chemoselective protection of thiols versus alcohols and phenols. The Tosvinyl group

O Arjona, R Medel, J Rojas, AM Costa, J Vilarrasa

Index: Arjona, Odon; Medel, Rocio; Rojas, Jenny; Costa, Anna M.; Vilarrasa, Jaume Tetrahedron Letters, 2003 , vol. 44, # 34 p. 6369 - 6373

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Citation Number: 24

Abstract

The conjugate addition of aliphatic and aromatic thiols to ethynyl p-tolyl sulphone (tosylacetylene) has been managed to afford Tosvinyl derivatives chemoselectively (in the presence of oxygen nucleophiles) and stereoselectively (isomers Z) in practically quantitative yields. The conditions of choice are: catalytic amounts of Et3N (only 0.5–1.0 mol%), a reaction temperature around 0° C and, for the less acidic thiols, CF3CH2OH or ...