The alpha-Effect in Benzyl Transfers from Benzylphenylmethyl Sulfonium Salts to N-Methylbenzohydroxamate Anions.

The investigation of the occurrence of the alpha-effect in group transfers from phenyldialkyl sulfonium ions where one alkyl group is benzyl allows an assay of the effect of changing the nature of the C atom being transferred. The size of the alpha-effect responds to increasing electron demand, as methyl transfers do. Quantitative relationships between the size of the alpha-effect are established from both the nucleophilic side and the leaving group side of the S(N)2 transition state.