ChemInform Abstract: Preparation of Bicyclic Compounds from the Products of Conjugate Addition of Allylic Sulphoxide and Phosphine Oxide Carbanions to Cyclopent- 2-enones.

ChemInform Abstract

Lewis-acid catalyzed cyclization of the vinyl thioether (IV) produces the bicyclo(3.3.0)octanone (V). The isomers (VI) are prepared in a similar manner. The vinylic sulfoxide (VII) and the phosphine oxides (IX) and (XI) undergo base-catalyzed cyclization, yielding the bicyclo-(2.2.1)heptanones (VIII), (X), and (XII). The bicyclo(3.2.1)octanols (XIII) and (XIV) are obtained from (VII) and (IX) by treatment with lithium diisopropylamide. In contrast, the unsaturated lactone (XV) leads to the formation of the cyclohexanone (XVI) by ring-opening of the initial adduct.