REACTION OF THIOSULFINATES WITH TRIHALOACETIC ANHYDRIDES. II. ADDITION OF SULFENYL TRIHALOACETATES TO OLEFINS

Abstract Treatment of thiolsulfinates with trifluoro- or trichloroacetic anhydride at -20°C in the presence of various olefins in carbon tetrachloride afforded the corresponding β-trifluoro- or trichloroacetoxy sulfides in good yields. The β-trihaloacetoxy sulfides are considered to be resulted by the electrophilic addition of the sulfenyl trihaloacetates, formed as transient intermediates, to olefins. The addition takes place stereospecifically in trans manner and the regioselectivity for the addition with unsymmetrical olefins obeyed the Markownikoff orientation rule, except 3,3-dimethyl-1-butene which gave initially the anti-Markownikoff product 3 due to the steric hindrance, however the adduct 3 is readily converted to the Markownikoff product 22 upon heating. Since the addition is highly regioselective and stereospecific, this is a very convenient procedure for the syntheses of β-trihalo-acetoxy sulfides.