Catalytic Carbon-Carbon Bond Activation of Saturated and Unsaturated Carbonyl Compounds via Chelate-Assisted Coupling Reaction with Indoles
Catalytic Carbon-Carbon Bond Activation of Saturated and Unsaturated Carbonyl Compounds via Chelate-Assisted Coupling Reaction with Indoles
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DOI：
10.1021/acscatal.0c01245
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发表时间：
2020-05-15
期刊：
影响因子：
12.9
通讯作者：
Yi, Chae S.
中科院分区：
文献类型：
--
作者：
Pannilawithana, Nuwan;Yi, Chae S.
设计了螯合物辅助策略来促进饱和和不饱和羰基化合物的高区域选择性催化C-C键活化反应。研究发现，Ru-H阳离子配合物1是一种有效的催化剂，可用于介导1，2-二取代吲哚与α，β-不饱和醛和酮的偶联反应，其中羰基底物的区域选择性C-alpha-C-beta活化可形成3-烷基吲哚产物。吲哚与饱和醛和酮的类似偶联反应直接导致羰基底物的C-alpha- C-beta裂解，形成3-allcylindole产物。1，2-二甲基亚油酸与（E）-3-壬烯-2-酮和2-丙醇-d（8）的偶联反应显示20-22%的氘掺入到3-烷基吲哚产物的α-和β-CH 2中。1，2-二甲基亚油酸与（E）-3-壬烯-2-酮的偶联反应对产物的α-碳表现出最显著的碳动力学同位素效应（C-alpha = 1.046）。由1，2-二甲基亚油酸与一系列对位取代的烯酮p-X-C6 H4 CH = CHCOCH 3（X = OMe，Me，H，Cl，CF 3）的反应构建的Hammett图显示了给电子基团的适度促进作用（rho = -0.2 +/-0.1）。通过NMR从Ru-H络合物1与1，2-二甲基吲哚和（E）-3-壬烯-2-酮在CD 2Cl 2中的化学计量反应混合物中检测到几种催化相关的Ru-H物种。这些结果支持了催化偶联反应的机理，通过共轭加成吲哚到烯酮，然后C-C键活化和氢解步骤。
The chelate assistance strategy was devised to promote a highly regioselective catalytic C-C bond activation reaction of saturated and unsaturated carbonyl compounds. The cationic Ru-H complex 1 was found to be an effective catalyst for mediating the coupling reaction of 1,2-disubstituted indoles with alpha,beta-unsaturated aldehydes and ketones, in which the regioselective C-alpha-C-beta activation of the carbonyl substrates has been achieved in forming the 3-alkylindole products. The analogous coupling reaction of indoles with saturated aldehydes and ketones directly led to the C-alpha- C-beta cleavage of the carbonyl substrates in forming the 3-allcylindole products. The coupling reaction of 1,2-dimethylinole with (E)-3-nonen-2-one and 2-propanol-d(8) showed 20-22% of deuterium incorporation to both alpha- and beta-CH2 of the 3-alkylindole product. The coupling reaction of 1,2-dimethylinole with (E)-3-nonen-2-one exhibited the most significant carbon kinetic isotope effect on the alpha-carbon of the product (C-alpha = 1.046). The Hammett plot constructed from the reaction of 1,2-dimethylinole with a series of para-substituted enones p-X-C6H4CH=CHCOCH3 (X = OMe, Me, H, Cl, CF3) showed a modest promotional effect by an electron-donating group (rho = -0.2 +/- 0.1). Several catalytically relevant Ru-H species were detected by NMR from a stoichiometric reaction mixture of the Ru-H complex 1 with 1,2-dimethylindole and (E)-3-nonen-2-one in CD2Cl2. These results support a mechanism of the catalytic coupling reaction via conjugate addition of indoles to enones followed by the C-C bond activation and hydrogenolysis steps.