Cu- and Pd-Catalyzed Asymmetric One-Pot Tandem Addition−Cyclization Reaction of 2-(2‘,3‘-Alkadienyl)-β-keto Esters, Organic Halides, and Dibenzyl Azodicarboxylate: An Effective Protocol for the Enantioselective Synthesis of Pyrazolidine Derivatives
摘要:
Optically active pyrazolidine derivatives have been constructed by the Cu- and Pd-catalyzed asymmetric one-pot tandem addition-cyclization reaction of 2-(2',3'-dienyl)-beta-ketoesters, organic halides, and dibenzyl azodicarboxylate. The absolute configurations of the final products depend on the structure of the ligand.
Cu- and Pd-Catalyzed Asymmetric One-Pot Tandem Addition−Cyclization Reaction of 2-(2‘,3‘-Alkadienyl)-β-keto Esters, Organic Halides, and Dibenzyl Azodicarboxylate: An Effective Protocol for the Enantioselective Synthesis of Pyrazolidine Derivatives
Optically active pyrazolidine derivatives have been constructed by the Cu- and Pd-catalyzed asymmetric one-pot tandem addition-cyclization reaction of 2-(2',3'-dienyl)-beta-ketoesters, organic halides, and dibenzyl azodicarboxylate. The absolute configurations of the final products depend on the structure of the ligand.
Highly Diastereoselective Palladium-Catalyzed Cyclizations of 3,4-Allenylic Hydrazines and Organic Halides—Highly Stereoselective Synthesis of Optically Active Pyrazolidine Derivatives and the Prediction of the Stereoselectivity
作者:Qing Yang、Xuefeng Jiang、Shengming Ma
DOI:10.1002/chem.200700620
日期:2007.11.16
Pyrazolidines containing two chiral centers, an interesting class of heterocyclic compounds possessing a range of biological activities, have been prepared highly diastereoselectively (up to 95:5) through asymmetric Pd(OAc)(2)-catalyzed cyclizations between the easy available opticallyactive allenylic hydrazines and organic halides in THF in the presence of (R,R)-Bn-Box (L2) as the ligand. It was