Photo‐Excited Nickel‐Catalyzed Silyl‐Radical‐Mediated Direct Activation of Carbamoyl Chlorides To Access (Hetero)aryl Carbamides**
摘要:
AbstractAmide bonds connect the amino acids in proteins and exist as a prevalent structural motif in biomolecules. Herein, we have exploited the concept of cross‐electrophile coupling by merging the photo‐redox and transition‐metal catalysis to construct carbamides from superabundant (hetero)aryl halides along with commercially feasible carbamoyl chlorides. The success of this method relies on the prior formation of NiII‐aryl halide intermediates, which involves in a photoexcited Ni‐halide homolysis event by energy transfer from aryl bromide and single‐electron transfer from aryl chloride to assist generation of the vital carbamoyl radical. The breadth of application of this technique is demonstrated both in inter‐ as well as intramolecular routes for the synthesis of a plethora of (hetero)aryl carbamides with diverse functionalities, and biologically important benzolactams.
TMSOTf acts as Lewis acid to activate carbamoyl chlorides and generates highly electrophilic carbamoyl triflates in situ; these are active species for late‐stage aromatic carbamoylation.
Asymmetric Synthesis of Propargylic α-Stereogenic Tertiary Amines by Reductive Alkynylation of Tertiary Amides Using Ir/Cu Tandem Catalysis
作者:Toolika Agrawal、Kimberly D. Perez-Morales、Jermaine A. Cort、Joshua D. Sieber
DOI:10.1021/acs.joc.2c00131
日期:2022.5.6
The development of an asymmetric protocol for the reductive alkynylation of amides to access important α-stereogenic tertiary propargylic amines is reported using a tandem Ir-catalyzed hydrosilylation/enantioselective Cu-catalyzed alkynylation. The reaction utilizes a Cu/PyBox catalyst system in the alkynylation step to achieve asymmetry and affords excellent yields with moderate to good levels of
据报道,使用串联 Ir 催化的氢化硅烷化/对映选择性 Cu 催化的炔基化,开发了一种不对称方案,用于酰胺的还原炔基化以获取重要的 α-立体异构叔炔丙基胺。该反应在炔基化步骤中使用 Cu/PyBox 催化剂体系来实现不对称性,并在使用低 Ir 催化剂负载量 (0.5 mol%) 的同时提供出色的产率和中等至良好的对映体控制水平。
Rh<sup>III</sup>-Catalyzed Synthesis of Cyclopenta[<i>b</i>]carbazoles via Cascade C–H/C–C Bond Cleavage and Cyclization Reactions: Using Amide as a Traceless Directing Group
作者:Yanwei Wang、Bin Li、Baiquan Wang
DOI:10.1021/acs.orglett.9b03969
日期:2020.1.3
Rhodium-catalyzed cascade C-H/C-C cleavage and cyclization reactions of 3-amide substituted indoles with diynes to construct cyclopenta[b]carbazoles have been developed. A strategy amide worked as a novel traceless directing group along with C-C bondcleavage via Friedel-Crafts-retro reaction has been disclosed in this protocol. This method exhibits a broad substrate scope and tolerates various functional
The invention relates to novel substituted dibenzo[d,d′]benzo[1,2-b;4,5-b′]dithiophenes (DBBDT), to methods of their synthesis, to organic semiconducting materials, formulations and layers comprising them, and to electronic devices, like organic field effect transistors (OFETs), comprising them.