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Cleavage of C(aryl)−CH 3 Bonds in the Absence of Directing Groups under Transition Metal Free Conditions
Author(s) -
Dai PengFei,
Ning XiaoShan,
Wang Hua,
Cui XianChao,
Liu Jie,
Qu JianPing,
Kang YanBiao
Publication year - 2019
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201901783
Subject(s) - chemistry , aryl , decarboxylation , cleavage (geology) , pyridine , transition metal , borylation , bond cleavage , intermolecular force , photochemistry , stereochemistry , medicinal chemistry , polymer chemistry , organic chemistry , molecule , alkyl , catalysis , materials science , fracture (geology) , composite material
Organic chemists now can construct carbon–carbon σ‐bonds selectively and sequentially, whereas methods for the selective cleavage of carbon–carbon σ‐bonds, especially for unreactive hydrocarbons, remain limited. Activation by ring strain, directing groups, or in the presence of a carbonyl or a cyano group is usually required. In this work, by using a sequential strategy site‐selective cleavage and borylation of C(aryl)−CH 3 bonds has been developed under directing group free and transition metal free conditions. Methyl groups of various arenes are selectively cleaved and replaced by boryl groups. Mechanistic analysis suggests that it proceeds by a sequential intermolecular oxidation and coupling of a transient aryl radical, generated by radical decarboxylation, involving a pyridine‐stabilized persistent boryl radical.