Photochemical Organocatalytic Benzylation of Allylic C–H Bonds
作者:Emilien Le Saux、Margherita Zanini、Paolo Melchiorre
DOI:10.1021/jacs.1c11712
日期:2022.1.26
We report a radical-based organocatalytic method for the direct benzylation of allylic C–H bonds. The process uses nonfunctionalized allylic substrates and readily available benzyl radical precursors and is driven by visible light. Crucial was the identification of a dithiophosphoric acid that performs two distinct catalytic roles, sequentially acting as a catalytic donor for the formation of photoactive
amines and carboxylicacids that complement the popular amide coupling can significantly expand accessible chemical space if they yield products distinct from the classic R–NHC(O)–R′ amide arrangement. Here we have developed an amine–acid esterification reaction based on pyridinium salt activation of amine C–N bonds to create products of type R–OC(O)–R′ upon reaction with alkyl and aryl carboxylic acids
Visible-Light-Mediated Deaminative Three-Component Dicarbofunctionalization of Styrenes with Benzylic Radicals
作者:Felix J. R. Klauck、Hyung Yoon、Michael J. James、Mark Lautens、Frank Glorius
DOI:10.1021/acscatal.8b04191
日期:2019.1.4
The visible-light-mediated three-component dicarbofunctionalization of styrenes using simple benzylic radicals is described. Notably, this work describes a rare example of undirected dicarbofunctionalization using unsubstituted benzyl radicals. Key to the success of this strategy was the rational design and use of benzylic pyridinium salts as radical precursors. Using this approach, abundant styrenes, electron-rich heterocycles, and benzylic amines were combined to rapidly afford a number of densely functionalized 1,1-diarylalkanes. A dipeptide-derived pyridinium salt was applied in this transformation, which resembles a visible-light-mediated deaminative generation of radicals from peptides.