The solvolysis of trans 1,2-diphenyl-2-phenylthio13C>vinyl tosylate in anhydrous or aqueous acetic acid

Article abstract of DOI:10.1139/v82-109

The acetolysis of trans-1,2-diphenylthio<1-¹³C>vinyl tosylate (2-OTs-1-¹³C) under anhydrous conditions (HOAc-Ac2O-NaOAc) gave trans-1,2-diphenyl-2-phenylthio<1,2-¹³C>vinyl acetate (2-OAc-1,2-¹³C) as product.The label was scrambled equally over C-1 and C-2 and there was no detectable amount of cis-product.These results are consistent with the involvement of an intermediate sulfur-bridged thiirenium ion in the reaction.Sovolysis of 2-OTs-1-¹³C in 70percent HOAc - 30percent H2O containing 3 equiv. of NaOAc gave 1,2-diphenyl-2-phenylthio<1,2-¹³C>ethanone(α-phenyl-α-(phenylthio)acetophenone) (5-1,2-¹³C) and 1,2-diphenyl<1,2-¹³C>ethanone (desoxybenzoin) (6-1,2-¹³C) as major and minor products, respectively.The ¹³C-label in both of these ketones was again equally distributed over C-1 and C-2.Further studies with unlabeled 2-OTs showed that its solvolysis in aqueous HOAc gave , besides ketones 5 and 6, some benzil and diphenyl disulfide.It was also found that 6, benzil, and diphenyl disulfide were derived from the initial product 5.A possible mechanism for these conversions is proposed.