VARIABLE ELECTRONIC-PROPERTIES OF THE CSNME2 GROUP

The sigma-I value for the CSNMe2 group has been determined and the value of 0.23 indicates that this group is inductively electron withdrawing. The effect of the p-CSNMe2 group on the solvolysis rate of cumyl chloride has also been determined and, relative to the p-H analogue, this group has a negligible effect on rate. p-CSNMe2 substitution slows the hydrolysis rate of substituted benzaldehyde dimethyl acetals. p-CSNMe2 substitution enhances the solvolysis rate of ArCH(OMs)PO(OEt)2. These variable rate effects on reactions involving cationic intermediates have been interpreted in terms of variable electronic properties of the CSNMe2 group. This group can be cation stabilizing, electroneutral, or cation destabilizing, depending on the charge demands of specific cations. This is a result of a conjugative interaction of CSNMe2 with a cationic center and resultant delocalization of positive charge onto sulfur. The importance of such conjugation is a function of the amount of transition-state charge developed on the carbon bearing the CSNMe2 group. The electronic effects of the amphielectronic p-CSNMe2 group are compared to the more conventional effects of CONMe2 and the m-CSNMe2 analogues.