INTRAMOLECULAR NITRILE OXIDE CYCLOADDITION ON CHIRAL OLEFINS - A STEREOCONTROLLED APPROACH TO BETA-KETOL PRECURSORS

The intramolecular nitrile oxide cycloaddition reaction on chiral (E) and (Z) olefins featuring a sulphur atom along the carbon chain connecting dipole and dipolarophile occurs with poor to excellent anti stereoselectivity, which is mainly affected by the substitutents at the allylic stereocenter. The possibility of converting the cycloadducts into stereoisomerically pure β-ketols has been established in one case.