Intramolecular Coupling of Allyl Carboxylates with Allyl Stannanes and Allyl Silanes: A New Type of Reductive Elimination Reaction?
作者:María Méndez、Juan M. Cuerva、Enrique Gómez-Bengoa、Diego J. Cárdenas、Antonio M. Echavarren
DOI:10.1002/1521-3765(20020816)8:16<3620::aid-chem3620>3.0.co;2-p
日期:2002.8.16
substrates substituted at C-3 of the allyl and/or alkene terminus. The palladium-catalyzed intramolecular coupling of allyl silanes with allyl trifluoroacetates allows the synthesis of trans five-membered-ring carbocycles and requires the use of a bicyclic phosphite as the ligand. DFT calculations suggest that the preferred pathway for the intramolecular allyl/allyl coupling is by formation of the Cbond;C
烯丙基锡烷与烯丙基羧酸盐的钯催化的分子内偶联提供了五元和六元环碳环的一般合成。分子内偶联选择性地导致反式五元碳环和顺式六元碳环,而与起始材料中烯丙基功能的顺式或反式构型无关。例如,10-表异构体的立体选择性合成证明了六元碳环的顺式构型。相关的Oppolzer环化导致底物在烯丙基和/或烯烃末端的C-3处取代,导致收率降低或完全失败。烯丙基硅烷与烯丙基三氟乙酸酯的钯催化分子内偶联可合成反式五元环碳环,并需要使用双环亚磷酸酯作为配体。DFT计算表明,分子内烯丙基/烯丙基偶联的优选途径是通过在双(η(3)-烯丙基)钯配合物的烯丙基配体的C-3末端之间形成Cbond; C键。