Selective C-C bonds formation, N-alkylation and benzo[d]imidazoles synthesis by a recyclable zinc composite
作者:Guanxin Zhu、Zheng-Chao Duan、Haiyan Zhu、Dongdong Ye、Dawei Wang
DOI:10.1016/j.cclet.2021.06.060
日期:2022.1
reaction, dehydrogenation and heterocycles synthesis, instead of noble metals. The uniformly dispersed zinc composites were designed, synthesized and carefully characterized by means of XPS, EDS, TEM and XRD. The resulting zinc composite showed good catalytic activity for the N-alkylation of amines with amines, ketones with alcohols in water under base-free conditions, while unsaturated carbonyl compounds
Tunable Triazole-Phosphine-Copper Catalysts for the Synthesis of 2-Aryl-1<i>H</i>
-benzo[d]imidazoles from Benzyl Alcohols and Diamines by Acceptorless Dehydrogenation and Borrowing Hydrogen Reactions
作者:Zhaojun Xu、Duo-Sheng Wang、Xiaoli Yu、Yongchun Yang、Dawei Wang
DOI:10.1002/adsc.201700179
日期:2017.10.4
activity. Mechanistic studies and deuterium labeling experiments indicated that the reactions proceeded by an initial and reversible alcohol dehydrogenation resulting in a copper hydride intermediate. This was also supported by the direct observation of a diagnostic copper hydride signal by solid‐state infrared spectroscopy. The TAP−Cu‐H complex showed absorptions at 912 cm−1 that could be assigned
三唑-膦-铜配合物(TAP-Cu)已被合成并用作可调谐和有效的催化剂,用于选择性合成氟代2-芳基-1 H-苯并[d]咪唑和1-苄基-2-芳基1小时一步法制得的简单醇中的苯并[d]咪唑衍生物。TAP-Cu对脱氢和借用氢反应均显示出优异且可调节的催化活性,首次证明了80多个例子。观察到配体在催化剂活性中起关键作用。机理研究和氘标记实验表明,反应是通过初始且可逆的醇脱氢进行的,从而生成氢化铜中间体。固态红外光谱法直接观察氢化铜诊断信号也支持了这一点。TAP-Cu-H络合物在912 cm -1处显示吸收可以分配给氢化铜拉伸。此外,也成功地进行了中间双亚胺的直接捕集。
Substrate-controlled Rh(<scp>iii</scp>)-catalyzed regiodivergent annulation towards fused and spiro benzimidazoles
作者:Ying-Ti Huang、Indrajeet J. Barve、Yi-Ting Huang、Sandip Dhole、Wei-Jung Chiu、Chung-Ming Sun
DOI:10.1039/d2ob00906d
日期:——
Mechanistically, C–H activation followed by migratory insertion of maleimide forms a Heck-type intermediate. Unsubstituted benzimidazole undergoes aza-Michael addition to form a (4 + 2) fused product, whereas ortho-substituted phenyl benzimidazole causes steric clash to deliver a (4 + 1) spiro-adduct favorably via acid-catalyzed intramolecular annulation.
Rapid Synthesis of Benzimidazole-Fused Isoindoles by Rh(III)/Ru(II)-Catalyzed [4 + 1] Cascade C–H/N–H Annulation of 2-Arylbenzimidazoles with Alkynoates and Alkynamide
作者:Ying-Ti Huang、Indrajeet J. Barve、Ganesh P. Pawar、Chung-Ming Sun
DOI:10.1021/acs.joc.3c00937
日期:2023.8.4
A Rh(III)-catalyzed [4 + 1] cyclization of 2-arylbenzimidazoles with alkynoates through C–H activation/ortho-alkenylation/intramolecular annulation cascade to obtain benzimidazole-fused isoindoles is reported. The reaction of the Rh catalyst and internal alkyne ester provides benzo[4,5]imidazo[2,1-a]isoindole acetate exclusively. Conversely, internal alkyne amide participates in the annulation process
Copper Catalyzed N-Arylation of Amidines with Aryl Boronic Acids and One-Pot Synthesis of Benzimidazoles by a Chan–Lam–Evans N-Arylation and C–H Activation/C–N Bond Forming Process
Mono-N-arylation of benzamidines 1 with aryl boronic acids 2 was effectively achieved in the presence of a catalytic amount of Cu(OAc)(2) and NaOPiv under mild aerobic conditions. Combining this step with an intramolecular direct C-H bond functionalization, catalyzed by the same catalytic system but under oxygen at 120 degrees C, afforded benzimidazoles 3 in good to excellent yields.