Participation by Ether Oxygen (RO-3) in the Hydrolysis of Sulfonate Esters of 2-Methoxyethanol and 2-Methoxy-2-methyl-1-propanol. Implications Regarding the Nonlinear Ethanol-Trifluoroethanol Plot for Mustard Chlorohydrin

Article abstract of DOI:10.1021/jo00388a032

The lack of scrambling with deuterium-labeled reactants, a nonlinear ethanol-trifluoroethanol plot, and rate acceleration by edded thiourea are used to show that sulfonate esters of methoxyethanol (MeOCH2CH2OH) undergo solvent-assisted displacement in a variety of solvents; neighboring group participation by ether oxygen (RO-3 participation) does not occur.This conclusion is in accord with predictions of rate based on the Taft treatment of substituent effects.On the other hand, the branched derivative MeOCMe2CH2OBs reacts with concerted RO-3 participation to give completely rearranged product.It solvolysis rate is insensitive to added thiourea, the Taft treatment predicts modest anchimeric assistance, and a linear ethanol-trifluoroethanol plot is observed.We discuss the implications of these results relative to the previously observed nonlinear plot for mustard chlorohydrin.