Highly stereoselective and easy synthesis of enantiopure phosphoranyl oxiranes

The highly stereoselective synthesis of enantiopure phosphoranyl alkyl oxiranes has been accomplished by the addition of a nucleophilic stable phosphino(silyl)carbene to chiral aldehydes prepared from (−)-verbenone and d-mannitol, respectively. In the process, two new stereogenic centers are created one of them being on an oxirane quaternary carbon. The excellent π-facial diastereoselection of the aldehydes combined with the diastereoselectivity of the carbene addition allowed us to synthesize the title compounds as single stereoisomers with well defined absolute configuration.