Enantioselective Iridium-Catalyzed Allylic Alkylation of Racemic Branched Alkyl-Substituted Allylic Acetates with Malonates
作者:Tian-Yuan Zhang、Yi Deng、Kun Wei、Yu-Rong Yang
DOI:10.1021/acs.orglett.0c04309
日期:2021.2.5
The regio- and enantioselective allylic substitution of branched alkyl-substituted allylic acetates employing malonates has been achieved through a process that calls for Krische’s π-allyliridium C,O-benzoate catalyst. The protocol reported herein can be applied to a diverse set of branched alkyl substrates that are generally not well tolerated in the other two types of Ir-catalyzed allylation.
We have presented the first palladium(II)‐thiadiazole‐ligand catalytic system, employing 1,3,4‐thiadiazole derivative as ligand to achieve the esterification of terminal olefin with excellent regio‐ and stereoselectivity. This work is significant in that it represented the first application of 1,3,4‐thiadiazole in organic synthesis. Furthermore, it was also featured by its satisfied yields, mild reaction
Iron-catalysed allylation–hydrogenation sequences as masked alkyl–alkyl cross-couplings
作者:Josef Bernauer、Guojiao Wu、Axel Jacobi von Wangelin
DOI:10.1039/c9ra07604b
日期:——
organomagnesium reagents (alkyl, aryl) with simple allyl acetates proceeds under mild conditions (Fe(OAc)2 or Fe(acac)2, Et2O, r.t.) to furnish various alkene and styrene derivatives. Mechanistic studies indicate the operation of a homotopic catalyst. The sequential combination of such iron-catalysed allylation with an iron-catalysed hydrogenation results in overall C(sp3)–C(sp3)-bond formation that constitutes
在温和条件下(Fe(OAc) 2或 Fe(acac) 2 , Et 2 O, rt),有机镁试剂(烷基、芳基)与简单的乙酸烯丙酯发生铁催化烯丙基化反应,得到各种烯烃和苯乙烯衍生物。机理研究表明了同伦催化剂的运作。这种铁催化烯丙基化与铁催化氢化的顺序组合导致整体C(sp 3 )–C(sp 3 )-键形成,这构成了具有挑战性的与烷基卤化物的直接交叉偶联方案的有吸引力的替代方案。
nickel and chiralamine cooperative catalysis to enable a highlyenantioselectiveallylic alkylation reaction between α-branched aldehydes and a wide scope of allyl esters, allowing the all-carbon quaternary stereocenter to be accessed with excellent enantioselectivity (up to 98% ee) and structural diversity. The general synthetic applicability has been showcased by the enantioselective synthesis of
全碳四元立体中心构成了天然产物和生物活性化合物的重要组成部分。在这里,我们公开了一种镍和手性胺协同催化,使 α-支化醛和各种烯丙基酯之间发生高度对映选择性的烯丙基烷基化反应,从而以优异的对映选择性(高达 98% ee ) 和结构多样性。关键手性构件的对映选择性合成以获取 (+)-依他佐辛、(-)-aphanorphine 和其他两种生物活性化合物,展示了一般合成适用性。
Palladium-Catalyzed Tandem Dehydrogenative [4 + 2] Annulation of Terminal Olefins with <i>N</i>-Sulfonyl Amides via C–H Activations
作者:Manman Sun、Weida Chen、Xiangyu Xia、Guodong Shen、Yongmin Ma、Jianguo Yang、Hanfeng Ding、Zhiming Wang
DOI:10.1021/acs.orglett.0c01011
日期:2020.4.17
palladium-catalyzed tandem dehydrogenative [4 + 2] annulation of terminalolefins with N-sulfonyl amides via C(sp2)–H activation, allylicC(sp3)–H activation, and homoallylic C(sp3)–H elimination processes has been developed. Promoted by the DMSO ligand, various benzamides, heterocyclic arylamides, alkenyl carboxamides, and commercial olefins are found to be efficient substrates to construct important heterocyclic