Studies on chiral organo-sulfur compounds. II. Stereochemistry of thermal chiral allyl sulfinate-sulfone rearrangements.

A highly efficient and general synthetic route to optically active sulfinates by the stereospecific boron trifluoride etherate-catalyzed esterification of sulfinamides was developed. Dramatic solvent effects were observed in the thermal transformation of allyl sulfinate derivatives to sulfones. Heating of chiral trans-and cis-allyl sulfinates, (S)-(-)-3a, c, e and (S)-(-)-3b, d, f, in N, N-dimethylformamide at 90-120°C provided chiral sulfones (S)-(+)-and (R)-(-)-5, 6, 7 in good yields, respectively, with exceedingly high stereospecificity.