REACTIONS OF β-HALOSULPHONES WITH BASES AND SILVER SALTS: THE SULPHONYL GROUP AS A WEAK ANCHIMERIC ASSISTANT

Article abstract of DOI:10.1016/S0040-4020(01)90317-5

In order to obtain evidence about the ability of the sulphone group as anchimeric assistant, the behaviour of the erythro and threo-1,2-dimethyl (and 1,2-diphenyl)-2-halo-1-methylsulphonylethanes in their reactions with NH4OH/CH3CN, NaOH/MeOH and AgBF4/MeOH is described.The participation is not detected in any case on butane derivates or on 1,2-diphenylethane derivatives with basic nucleophiles, which yielded mainly elimination products.Reactions of the last compounds with AgBF4/MeOH only afforded mixtures of substitution products, with predominance of those with the same configuration of the starting sulphones in the case of erythro-derivatives, which must only evolve through an S_N1 mechanism in competition with the anchimeric assistant process.This is the first reported result suggesting that the weak nucleophilic character of the sulphonylic oxygens can determine its participation as anchimeric assistant in the substitution of good leaving groups in β-position.