The steric course of the hydrolysis of racemic 3,4-epoxytetrahydropyran promoted by rabbit liver microsomal epoxide hydrolase has been investigated. Both enantiomers of the epoxide give (-)-(R,R)-trans-tetrahydropyran-3,4-diol at practically equal rates, the optical purity being at least 96% at any stage of conversion. These results can be justified by assuming that both enantiomers react in the 1,2-M conformation, nucleophilic attack by water taking place exclusively at position 3 of the 3S,4R enantiomer and at position 4 of the 3R,4S one, in contrast with the nonenzymic ring opening in which a high preference for attack at C(4) has been found.
UNUSUAL STERIC COURSE OF THE EPOXIDE HYDROLASE CATALYZED-HYDROLYSIS OF (+/-)3,4-EPOXYTETRAHYDROPYRAN - A CASE OF COMPLETE STEREO-CONVERGENCE
CATELANI, GIORGIO;
1981-01-01
Abstract
The steric course of the hydrolysis of racemic 3,4-epoxytetrahydropyran promoted by rabbit liver microsomal epoxide hydrolase has been investigated. Both enantiomers of the epoxide give (-)-(R,R)-trans-tetrahydropyran-3,4-diol at practically equal rates, the optical purity being at least 96% at any stage of conversion. These results can be justified by assuming that both enantiomers react in the 1,2-M conformation, nucleophilic attack by water taking place exclusively at position 3 of the 3S,4R enantiomer and at position 4 of the 3R,4S one, in contrast with the nonenzymic ring opening in which a high preference for attack at C(4) has been found.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
