The formation of bicyclo[n.2.0]alkan-1-ols from the reaction of the lithium enolates of simple ketones and phenyl vinyl sulfoxide

Abstract

The enolates generated from cyclopentanone, cycloheptanone or cyclooctanone and LDA at −78 °C in THF react with (±)-phenyl vinyl sulfoxide under controlled conditions of temperature, reaction time, and concentration. Upon oxidation with MCPBA of the product mixtures, the novel sulfonylbicyclo[3.2.0]heptan-1-ols 10–12, sulfonylbicyclo[5.2.0]nonan-1-ols 16–18, and sulfonylbicyclo[6.2.0]decan-1-ols 21 and 22 in conjunction with alkylated ketones 8, 9, 15, 19 and 20 were obtained from the respective ketones. The enolate generated from cyclobutanone and LDA at −78 °C in THF reacts with (±)-phenyl vinyl sulfoxide and upon oxidation with MCPBA, the cyclohexanone 4 and monoalkylated cyclobutanone 5 were obtained. The ratio of bicyclo[n.2.0]alkan-1-ol to alkylated products varied with the ketone enolate, conversion of phenyl vinyl sulfoxide, time, temperature and concentration of reaction and the stability and steric strain of the final bicyclo[n.2.0]alkan-1-ol product.