Efficient and Reusable PdCl2(MeCN)2/CuCl2/PEG-400 System for Cyclization of Alkenyl β-Keto Esters and Amides
摘要:
PEG-400 [poly(ethylene glycol-400)] was found as an effective medium for the PdCl(2)(MeCN)(2)-catalyzed hydroalkylation cyclization of alkenyl beta-keto esters and amides. In PEG-400, no additives such as Me(3)SiCl and Ln(OTf)(3) were required for the complete conversion of alkenyl beta-keto esters. The results also showed that CuCl(2) could promote the reaction. In the presence of PdCl(2)(MeCN)(2), CuCl(2), and PEG-400, various alkenyl beta-keto esters and amides underwent a selective cyclization reaction to give good to excellent yields of the desired six-membered-ring carbocycles. Furthermore, the PdCl(2)(MeCN)(2)/CuCl(2)/PEG-400 system could be recycled and reused five times without any loss of catalytic activity.
Palladium-Catalyzed Intramolecular Hydroalkylation of Alkenyl- ?-Keto Esters, ?-Aryl Ketones, and Alkyl Ketones in the Presence of Me3SiCl or HCl
作者:Xiaoqing Han、Xiang Wang、Tao Pei、Ross A. Widenhoefer
DOI:10.1002/chem.200400459
日期:2004.12.17
palladium-catalyzed hydroalkylation, but rather served as a source of HCl, which presumably catalyzes enolization of the ketone. Identification of HCl as the active promoter of palladium-catalyzed hydroalkylation led to the development of an effective protocol for the hydroalkylation of alkyl 3-butenyl ketones that employed sub-stoichiometric amounts of 2, HCl, and CuCl2 in a sealed tube at 70 degrees C.
Palladium-catalyzed cyclization of alkenyl β-keto esters in the presence of chlorotrimethylsilaneElectronic supplementary information (ESI) available: experimental procedures, analytical and spectroscopic data for new compounds and cyclohexanones. See http://www.rsc.org/suppdata/cc/b1/b111644d/
作者:Tao Pei、Ross A. Widenhoefer
DOI:10.1039/b111644d
日期:2002.3.7
PdCl2(CH3CN)2 catalyzed the cyclization of alkenyl beta-keto esters in the presence of a stoichiometric amount of SiMe3Cl to form 2-carboalkoxycyclohexanones in good yield with excellent regioselectivity.