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Site Directed Spin Labeling and EPR Spectroscopic Studies of Pentameric Ligand-Gated Ion Channels
Published on: July 4, 2016
Remote Spin-Center Shift Enables Activation of Distal Benzylic C─O and C─N Bonds
Li-Wen Hui1, Yee Lin Phang1, Chen-Yang Ye1
1State Key Laboratory of Precision and Intelligent Chemistry, Anhui Provincial Key Laboratory of Biomass Chemistry, Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China.
Abstract:
A spin-center shift (SCS) is a radical process that commonly involves a 1,2-radical shift along with the elimination of an adjacent leaving group by a two-electron ionic movement. The conventional SCS process is largely limited to 1,2-radical translocation, while a remote SCS event involving 1,n-radical translocation over a greater distance to enable distal bond functionalization remains largely underexplored. Herein, we report the boryl radical-promoted distal deoxygenation and deamination of free benzylic alcohols and simple benzylic amines, respectively, through a remote SCS event. The reaction was initiated by the addition of a 4-dimethylaminopyridine (DMAP)-boryl radical to the carbonyl oxygen atom of a benzoate or benzamide. Then, radical translocation took place across the aromatic ring to promote benzylic C─O or C─N bond cleavage. The resulting radical intermediate subsequently coupled with various alkenes to afford a wide range of alkylated products. The proposed mechanistic pathway was supported by experimental investigations.
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