An efficient enzymatic preparation of (+)- and (-)-conduritol E, a cyclitol with C2 symmetry

Lypozyme® IM (immobilised lipase from Mucor miehei) catalyses the enantiomeric alcoholysis of tetraacetylconduritol E (±)-2 to give enantiopure (1R,2R,3R,4R)-tetrahydroxycyclohex-5-ene (-)-1, and the unreacted ester (1S,2S,3S,4S)-tetraacetyloxycyclohex-5-ene, (+)-2. The latter was transformed by basic hydrolysis into (+)-1 in high yield and 95% ee. Selective amination of partial ester (-)-3, obtained by short alcoholysis of (±)-2, furnished the previously unreported conduramine F-4, (-)-4.