Stereochemical studies of the palladium-catalyzed rearrangements of chiral2-alkynyl sulfinates into chiral allenyl sulfones

Palladium-catalyzed reactions of diastereomerically pure chiral 2-alkynyl p -toluenesulfinates under very mild reaction conditions gave both enantiomer s of optically active sulfonyl allenes in good yields with high stereospeci ficity. The stereochemistry of this transformation with the assistance of a palladium catalyst was determined. The conversion rate was measured by the HPLC analysis in accordance with the elapse of the reaction time, and the rather marked difference of the rate was observed between the diastereomeri c sulfinates. A novel mechanism for this transformation with palladium cata lysts is proposed. (C) 2001 Elsevier Science Ltd. All rights reserved.