UNUSUALLY FACILE SOLVOLYSIS OF PRIMARY TOSYLATES - CASE FOR PARTICIPATION BY THE N-NITROSO GROUP

The acetolysis of the primary tosylates, N-methyl-N-nitroso-2-(tosyloxy)ethylamine (1) and N-methyl-N-nitroso-3-(tosyloxy)propylamine (2), gives the corresponding acetates in better than 80% isolated yields. The kinetic analysis of the acetolysis reactions indicated very rapid solvolysis. The activation parameters for 1 are ΔH‡ = 17 kcal/mol and ΔS‡ = -16.6 eu, and for 2 they are ΔH‡ = 18.5 kcal/mol and ΔS‡ = -21 eu. Acetolysis of the optically active secondary tosylate, (S)-N-methyl-N-nitroso-2-(tosyloxy)propylamine (4), resulted in net retention of configuration of the chiral reaction center. These data are best accounted for by invoking neighboring group participation by the N-nitroso function. The kinetic and stereochemical arguments were further bolstered by the isolation of the oxadiazolium ion 6a from 1 in nonnucleophilic media. © 1979, American Chemical Society. All rights reserved.