Palladium acetate and 1,4-bis(diphenylphosphino)butane (dppb) catalyze regioselective cyclocarbonylation of 4-allylsteroids forming exclusively 7- membered ring lactones with excellent yields (96-98 %). The stereoselective addition of an epoxide ring on the side-chain of steroids is realized by coupling the carbonyl group of the cyclopentanone ring of the steroid with 2- benzothiazolylchloromethyllithium 1 or 4,4-dimethyl-2- oxazolinylchloroalkylithiums 2 and 3.
Palladium (II) Catalyzed Regioselective Lactonization of Steroids. Chemoselective Construction of Novel Estrone Derivatives
CAPRIATI, Vito
1999-01-01
Abstract
Palladium acetate and 1,4-bis(diphenylphosphino)butane (dppb) catalyze regioselective cyclocarbonylation of 4-allylsteroids forming exclusively 7- membered ring lactones with excellent yields (96-98 %). The stereoselective addition of an epoxide ring on the side-chain of steroids is realized by coupling the carbonyl group of the cyclopentanone ring of the steroid with 2- benzothiazolylchloromethyllithium 1 or 4,4-dimethyl-2- oxazolinylchloroalkylithiums 2 and 3.File in questo prodotto:
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