Regioselective Synthesis of β-Aryl- and β-Amino-Substituted Aliphatic Esters by Rhodium-Catalyzed Tandem Double-Bond Migration/Conjugate Addition
作者:Dominik M. Ohlmann、Lukas J. Gooßen、Markus Dierker
DOI:10.1002/chem.201100654
日期:2011.8.16
unsaturated esters. Once the double‐bond is in conjugation with the carboxylate group, they also catalyze the Michael addition of carbon and nitrogen nucleophiles. In the presence of these catalysts, unsaturated carboxylates enter a dynamic equilibrium of positional and geometrical double‐bond isomers. The conjugated species are continuously removed through 1,4‐additions with formation of β‐amino esters or
Two new palladium‐catalyzed reactions of aromatic sulfur compounds enabled the conversion of dibenzothiophenes into triphenylenes in four steps. This transformation of one aromatic framework into another consists of 1) 4‐chlorobutylation of the dibenzothiophene to form the corresponding sulfonium salt, 2) palladium‐catalyzed arylative ring opening of the sulfonium salt with a sodium tetraarylborate
芳香族硫化合物的两个新的钯催化反应使二苯并噻吩在四个步骤中转化为苯并菲。一种芳族骨架向另一种芳族骨架的转化包括:1)二苯并噻吩的4-氯丁基化反应形成相应的sulf盐; 2)钯盐与四芳基硼酸钠的钯催化的芳基开环反应; 3)分子内S N 2反应以形成teraryl锍盐,和4)的钯催化的分子内ç S / C H至电palladation耦合。以量身定制的方式合成了所需的对称和不对称的三亚苯基,其总收率令人满意。
An Umpolung Approach to Alkene Carboamination: Palladium Catalyzed 1,2-Amino-Acylation, -Carboxylation, -Arylation, -Vinylation, and -Alkynylation
作者:Adele Faulkner、James S. Scott、John F. Bower
DOI:10.1021/jacs.5b03732
日期:2015.6.10
Pd(0)-catalyst into the N-O bond of O-pentafluorobenzoyl oxime esters generates imino-Pd(II) intermediates, which undergo 5-exo cyclization with sterically diverse alkenes. The resultant alkyl-Pd(II) intermediates are intercepted by organometallic nucleophiles or alcohols, under carbonylative or noncarbonylative conditions, to provide 1,2-carboamination products. This approach provides, for the first time,
Pd 催化的烯烃 1,2-碳化的传统方法依赖于亲核氮基组分和内部 C 基或外部氧化剂的组合。在这项研究中,我们概述了一种 umpolung 方法,该方法由亲电 N 基组件的氧化引发触发,并采用“标准”有机金属亲核试剂引入新的碳基片段。具体而言,将 Pd(0)-催化剂氧化加成到 O-五氟苯甲酰基肟酯的 NO 键中会生成亚氨基-Pd(II) 中间体,其与空间不同的烯烃进行 5-外环化。在羰基化或非羰基化条件下,生成的烷基-Pd(II) 中间体被有机金属亲核试剂或醇截获,以提供 1,2-碳化产物。这种方法提供,首次实现烯烃1,2-氨基-酰化、-羧化、-芳基化、-乙烯基化和-炔基化的统一策略。对于羰基化过程,五氟苯甲酸酯离去基团的协调原脱羧作用是反应效率的基础。该过程可能是相关 Narasaka-Heck 环化的关键特征,并解释了 O-五氟苯甲酰基肟酯在此类 aza-Heck 反应中的功效。
Enantioselective Synthesis of 1-Aryl Tetrahydroisoquinolines by the Rhodium-Catalyzed Reaction of 3,4-Dihydroisoquinolinium Tetraarylborates
omnipresent in biologically active molecules. Here we report on the direct asymmetric synthesis of these valuable compounds via the reaction of 3,4-dihydroisoquinolinium tetraarylborates. The dualroles of anionic tetraarylborates, which function as both prenucleophiles and stabilizers of 3,4-dihydroisoquinolinium cations, enable this rhodium(I)-catalyzed protocol to convergently provide enantioenriched 1-aryl