Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu, 610064, P. R. China.
College of Chemistry and Chemical Engineering, Neijiang Normal University, Neijiang, 641112, P. R. China.
Angew Chem Int Ed Engl. 2017 Dec 4;56(49):15683-15687. doi: 10.1002/anie.201704513. Epub 2017 Nov 8.
Reported herein is a novel visible-light photoredox system with Pd(PPh ) as the sole catalyst for the realization of the first direct cross-coupling of C(sp )-H bonds in N-aryl tetrahydroisoquinolines with unactivated alkyl bromides. Moreover, intra- and intermolecular alkylations of heteroarenes were also developed under mild reaction conditions. A variety of tertiary, secondary, and primary alkyl bromides undergo reaction to generate C(sp )-C(sp ) and C(sp )-C(sp ) bonds in moderate to excellent yields. These redox-neutral reactions feature broad substrate scope (>60 examples), good functional-group tolerance, and facile generation of quaternary centers. Mechanistic studies indicate that the simple palladium complex acts as the visible-light photocatalyst and radicals are involved in the process.
本文报道了一种新型可见光光氧化还原体系，该体系以 Pd(PPh ) 为唯一催化剂，实现了首例 N-芳基四氢异喹啉中 C(sp )-H 键与未活化的烷基溴的直接交叉偶联。此外，在温和的反应条件下，还发展了杂芳烃的分子内和分子间烷基化反应。各种叔、仲和伯烷基溴在中等至优异的收率下发生反应，生成 C(sp )-C(sp ) 和 C(sp )-C(sp ) 键。这些氧化还原中性反应具有广泛的底物范围（>60 个实例）、良好的官能团耐受性和易于生成季碳原子的特点。机理研究表明，简单的钯配合物作为可见光光催化剂，自由基参与反应过程。
