Effect of substitution of oxygen by sulfur in the npnleaving group of a carbonate: Kinetics of the phenolysis and benzenethiolysis of 5-methyl aryl thiocarbonates

Article abstract of DOI:10.1002/poc.1192

The phenolysis and benzenethiolysis of S-methyl 4-nitrophenyl thiocarbonate (1) and S-methyl 2,4-dinitrophenyl thiocarbonate (2) in water are studied kinetically. The Brnsted plots (log k_N versus nucleophile basicity) are linear for all reactions. The Bronsted slopes for 1 and 2 are, 0.51 and 0.66 (phenolysis) and 0.55 and 0.70 (benzenethiolysis), respectively. These values suggest a concerted mechanism for these reactions, as found in the corresponding carbonates. Namely, substitution of OMe by SMe in the nonleaving group does not change the mechanism. Copyright 2007 John Wiley & Sons, Ltd.