Lasky Matthew R, Salvador Tolani K, Mukhopadhyay Sukrit, Remy Matthew S, Vaid Thomas P, Sanford Melanie S
Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan, 48109, USA.
Corporate R&D, Dow, 1776 Building, Midland, Michigan, 48667, USA.
Angew Chem Int Ed Engl. 2022 Nov 14;61(46):e202208741. doi: 10.1002/anie.202208741. Epub 2022 Oct 17.
This report describes the development of a photochemical method for C(sp )-H pyridination that leverages the photoexcitation of electron donor-acceptor (EDA) complexes. Experimental and DFT studies show that black light (λ ≈350 nm) irradiation of solutions of protonated pyridines (acceptors) and aromatic C-H substrates (donors) results in single electron transfer to form aryl radical cation intermediates that can be trapped with pyridine nucleophiles under aerobic conditions. With some modification of the reaction conditions, this EDA activation mode is also effective for promoting the oxidatively triggered S Ar pyridination of aryl halides. Overall, this report represents an inexpensive and atom-economical approach to photochemical pyridination reactions that eliminates the requirement of an exogenous photocatalyst.
本报告描述了一种用于C(sp )-H吡啶化的光化学方法的开发，该方法利用了电子供体-受体（EDA）配合物的光激发。实验和密度泛函理论（DFT）研究表明，用黑光（λ≈350 nm）照射质子化吡啶（受体）和芳香族C-H底物（供体）的溶液会导致单电子转移，形成芳基自由基阳离子中间体，该中间体在有氧条件下可被吡啶亲核试剂捕获。通过对反应条件进行一些修改，这种EDA活化模式对于促进芳基卤化物的氧化引发的S Ar吡啶化也有效。总体而言，本报告代表了一种用于光化学吡啶化反应的廉价且原子经济的方法，该方法无需外源性光催化剂。
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