Preparation of Stable, Camphor-Derived, Optically Active Allyl and Alkyl Sulfoxides and Thermal Epimerization of the Allyl Sulfoxides

Article abstract of DOI:10.1021/jo00248a001

(+)-Camphor is converted by thioalkylation of the lithium enolate with allyl and alkyl p-toluenethiosulfonates into exo-3-(allylthio)- and exo-3-(alkylthio)camphors, which upon reduction with diisobutylaluminum hydride give the coresponding exo-(allylthio)- and exo-(alkylthio)isoborneols.Oxidation of the sulfides with m-chloroperbenzoic acid gives the exo-(allylsulfinyl)- and exo-(alkylsulfinyl)isoborneols in a stereochemically pure state.The configuration at sulfur in the sulfoxides is determined by X-ray crystalography of the allyl derivative to be S^S; this configuration implies that the exo-hydroxyl group at C2 controls the stereochemical outcome of the oxidation.The allylic sulfoxides are stable at room temperature, but upon heating through their melting points undergo a remarkable and generally quantitative rearrangement into the R^S epimers.