Asymmetric synthesis using organometallic reagents and optically pure vinylic sulfoxides

A new, general method is developed for preparation of various 3-substituted carbonyl compounds of very high optical purity. Application of this method is made to asymmetric synthesis of either enantiomer of 3-methylalkanoic acids, of optically pure 3-methylcyclopentanone, 3-methylcyclohexanone, 3-naphthylcyclopentanone 12 and 3-vinylcyclopentanone 14. 9,11-Seco steroid 12 and steroid intermediate 14 are precursors of optically pure steroidal equilenin and estrone of natural absolute configuration. The basis for this asymmetric synthetic method rests on the transfer of chirality from the sulfoxide sulfur atom to the 3-carbon carbon atom during organometallic 3-addition to optically pure α-carbonyl α.β-ethylenic sulfoxides.