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.
Enantio- and Diastereoselective Intermolecular Stetter Reaction of Glyoxamide and Alkylidene Ketoamides
作者:Qin Liu、Tomislav Rovis
DOI:10.1021/ol901081a
日期:2009.7.2
A triazolinylidene carbene catalyzed intermolecular Stetter reaction of glyoxamide and alkylidene ketoamides has been developed. 1,4-Dicarbonyl products are afforded in good to excellent yields, enantioselectivities, and diastereoselectivities. Further derivatization of the products affords useful intermediates for organic synthesis.
Lanthanide Triflate-Promoted Palladium-Catalyzed Cyclization of Alkenyl β-Keto Esters and Amides
作者:Dan Yang、Jin-Heng Li、Qiang Gao、Yi-Long Yan
DOI:10.1021/ol0349110
日期:2003.8.1
graphicsLanthanide triflates were found to promote the palladium-catalyzed cyclization of alkenyl beta-keto esters and amides. In the presence of catalytic amounts of PdCl2(MeCN)(2) and Ln(OTf)(3), various alkenyl beta-keto esters and amides underwent regioselective cyclization reactions to give six-, seven-, or eight-membered-ring carbocycles in moderate to excellent yields.
Lewis Acid Promoted Phenylseleno Group Transfer Tandem Radical Cyclization Reactions
作者:Dan Yang、Qiang Gao、On-Yi Lee
DOI:10.1021/ol025750n
日期:2002.4.1
[reaction: see text] A new Lewis acid promoted phenylseleno group transfer tandem radical cyclization method was developed. In the presence of Lewis acids such as Yb(OTf)3 or Mg(ClO4)2, under photolysis condition at low temperature (-45 degrees C), various unsaturated alpha-phenylseleno beta-keto amides underwent radical cyclization reactions to give monocyclic or bicyclic products in a highly efficient
Efficient and Reusable PdCl<sub>2</sub>(MeCN)<sub>2</sub>/CuCl<sub>2</sub>/PEG-400 System for Cyclization of Alkenyl <i>β</i>-Keto Esters and Amides
作者:Jin-Heng Li、Qi-Ming Zhu、Yun Liang、Dan Yang
DOI:10.1021/jo0506635
日期:2005.6.1
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.