Steroidal sulphur compounds. Part VI. Steric effects in the pyrolytic elimination of sulphinate esters

Abstract

Methyl 5α-cholestane-(R)- and 5α-cholestane-(S)-6β-sulphinates underwent pyrolytic syn-elimination, the rate of which depended upon chirality at sulphur. This was rationalized in terms of different steric compressions in diastereoisomeric five-membered cyclic transition states; the consequent allocations of configuration at sulphur were confirmed by conversion of the sulphinates into sulphoxides of known configuration. N.m.r. and o.r.d. data substantiated the configurational assignments.