Diastereoselectivity in the intermolecular Pauson-Khand reaction of chiral 2-alkynoates

Article abstract of DOI:10.1016/0040-4020(95)00152-X

Chiral 2-alkynoates have been readily prepared by condensation of several cyclohexyl- or camphor-based alcohols with 2-alkynoic acids or the corresponding acid chlorides. The hexacarbonyldicobalt complexes obtained therefrom reacted with olefins to afford the corresponding Pauson-Khand cyclopentenone adducts in good yields, with high regioselectivity, and with variable degrees of diastereoselectivity. In some instances, the degree of stereocontrol is superior to that observed for alkoxyacetylenes, so that the viability of an enantioselective approach to the intermolecular Pauson-Khand reaction of electron-deficient alkynes is demonstrated for the first time.