Regio- and stereoselective synthesis of (
E) - and (
Z) -vinyl sulfones, which made it feasible to investigate the stereochemistry of the conversion of vinyl sulfones to the corresponding allyl sulfones under basic conditions, was accomplished
via iodosulfonization of 1-alkenes or 1-alkynes. It was found that (
E) -vinyl sulfones preferentially afforded (Z) -allyl sulfones as kinetically-controlled products, while (
Z) - and α-substituted vinyl sulfones gave (
E) -allyl sulfones. Such stereochemical relationship was rationalized by “
syn-effect, ” and its relative degree for various substituents was determined by observation of
E/
Z ratios of the allyl sulfones resulted from the corresponding γ-mono- and disubstituted vinyl sulfones. X-ray crystallography was performed for some vinyl sulfones and the related compounds to reveal the origin of “
syn-effect.” On the other hand, the convenient new methods for the preparation of allyl sulfones and desulfonylation of their alkylated derivatives were successfully employed for the syntheses of squalene, (±) -recifeiolide, coenzyme Q
10, (±) -lavandulol, and isolavandulol.
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