Silver(I)–Ferrophox Catalyzed Enantioselective Desymmetrization of Cyclopentenedione: Synthesis of Highly Substituted Bicyclic Pyrrolidines
作者:Tapas Das、Prasenjit Saha、Vinod K. Singh
DOI:10.1021/acs.orglett.5b02582
日期:2015.10.16
A highly enantioselective desymmetrization of prochiral cyclopentene-1,3-dione via [3 + 2] cycloaddition of azomethine ylide using a silver(I)–ferrophox complex has been demonstrated. The method has been utilized in the synthesis of highly functionalized enantioenriched 5,5-fused bicyclic pyrrolidine derivatives under mild reaction conditions.
Mn(III)-Based Oxidative Free-Radical Cyclizations of Unsaturated Ketones
作者:Bridget McCarthy Cole、Luning Han、Barry B. Snider
DOI:10.1021/jo961199u
日期:1996.1.1
free-radical cyclization of unsaturated ketones is a versatile synthetic procedure with broad applicability. For example, oxidation of cyclopentanone 1a with 2 equiv of Mn(OAc)(3).2H(2)O and 1 equiv of Cu(OAc)(2).H(2)O in AcOH at 80 degrees C for 1.5 h affords 75% of bicyclo[3.2.1]oct-3-en-8-one 8a and 15% of bicyclo[3.2.1]oct-2-en-8-one 9a. Bridgedbicyclicketones that cannot enolize further are isolated
Chiral Phosphoric Acid Catalyzed Desymmetrization of Cyclopentendiones via Friedel–Crafts Conjugate Addition of Indolizines
作者:Qijian Ni、Zhiming Zhu、Yanjun Fan、Xiaoyun Chen、Xiaoxiao Song
DOI:10.1021/acs.orglett.1c03780
日期:2021.12.17
An organocatalytic highly diastero- and enantioselective Friedel–Crafts conjugate addition of indolizines to prochiral cyclopentenediones has been successfully developed. This desymmetric transformation provides a direct access to the desired indolizine-substituted cyclopentanediones in yields of 62–91% and excellent stereoselectivities. The utility of the approach was demonstrated by diverse late-stage
Chiral N-Heterocyclic-Carbene-Catalyzed Cascade Asymmetric Desymmetrization of Cyclopentenediones with Enals: Access to Optically Active 1,3-Indandione Derivatives
作者:Jia-Ming Hu、Jun-Qi Zhang、Bing-Bing Sun、Jun-Bo Chen、Jie-Qiang Yu、Xiao-Peng Yang、Hao-Peng Lv、Zheng Wang、Xing-Wang Wang
DOI:10.1021/acs.orglett.9b03178
日期:2019.11.1
A chiral N-heterocyclic-carbene-catalyzed cascade asymmetric desymmetrization reaction of cyclopentenediones with enals has been successfully initiated, followed with tandem aldol annulation, aromatization, as well as sequential methylation. The reactions proceeded well under mild reaction conditions, with broad substrate scope and good functional group tolerance, providing a rapid access to highly