Spiro γ-Lactones via Aluminum Enolate-Spiroepoxide Openings

Abstract

The opening of several spiroepoxides by aluminum ester enolates is described. The isolated γ -hydroxy esters are cyclized to the corresponding spirolactones with high efficiency. Alternatively, the crude product from epoxide opening may be directly converted to the spirolactone without purification of the intermediate hydroxy ester. This methodology provides another complementary route to 1-oxaspiro[4.n]-2-one systems that are of structural and biological interest.