Synthesis of p-toluenesulfonates 8b and 9b and of labelled analogs is
described and previous assignements of proton NMR signals for quaterna
ry methyl groups are confirmed. Acetolysis of these p-toluenesulfonate
s in the presence of NaOAc gave both substitution and elimination prod
ucts. Substitution could be accounted for by bimolecular processes (SN
2 on carbon, SAN on sulfur). Kinetics confirmed the intervention of bi
molecular processes for 8b. Elimination products came for a great pan
from intermediates formed by hydride and/or methyl shifts. All rearran
ged products could be explained by plain sigmatropic rearrangements or
by contact ion pair rearrangements. Attention is drawn to the close r
esemblance between sigmatropic rearrangements and contact ion pair rea
rrangements. (C) 1998 Elsevier Science Ltd. All rights reserved.