Boron-centred radicals (boryl radicals) are potential and attractive species in main group chemistry and synthetic chemistry. Recently, the development of boron compounds ligated by N-heterocyclic carbenes (NHCs) has sparked off advavnces in boryl radical chemistry because NHCs can highly stabilise boryl radicals by electronic and steric factors. This review highlights recent synthesis and reactions of such NHC-boryl radicals. From the standpoint of main group chemistry, examples of isolation or detection of unique NHC-boryl radicals are presented. From the standpoint of synthetic chemistry, on the other hand, the development of reactions of user-friendly NHC-boryl radicals, which has contributed to radical chemistry, organoboron chemistry and polymer science, is comprehensively described.
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http://dx.doi.org/10.1039/d1cs00385b | DOI Listing |
J Org Chem
December 2024
College of New Energy, State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580, P. R. China.
The photocatalytic dearomative 1,4-hydroboration of naphthalenes with an N-heterocyclic carbene borane (NHC-BH) complex was reported herein with controllable regioselectivity and chemoselectivity. This protocol yielded a wide range of naphthalene derivatives bearing various functional groups, notably bioactive compounds. Hydroboration occurred through the cooperation of photoredox and hydrogen atom transfer via boryl radical addition to naphthalene and further selective protonation.
View Article and Find Full Text PDFOrg Lett
December 2024
College of Chemistry, Zhengzhou University, Zhengzhou 450001, P. R. China.
NHC boryl radical mediated halogen atom transfer (XAT) is useful in organic synthesis. Yet, most of the reaction ends only with reducing the halogen to hydrogen, that is, the C-X to C-H. This is especially dominant for electron-deficient alkyl halides, where the formed electrophilic radical reacts rapidly with NHC boranes.
View Article and Find Full Text PDFOrg Lett
December 2024
Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
Nat Commun
November 2024
Key Laboratory of Molecule Synthesis and Function Discovery, Fujian Province University, College of Chemistry at Fuzhou University, Fuzhou, Fujian, 350108, China.
The catalytic asymmetric synthesis of axially chiral alkenes remains a daunting challenge due to the lower rotational barrier, especially for longer stereogenic axis (e.g. C-B axis).
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November 2024
Department of Chemical Physic, University of Science and Technology of China, Hefei, Anhui, 230026, China.
The advanced strategy using Lewis base-boryl radicals (LBRs) has recently been proposed for the addition of alkyl substituents to the full-carbon quaternary center of an organic molecule. However, as the rate-determining step in the whole route, reaction rate constants of LBRs with substrates are extremely lacking. In this paper, 4-dimethylaminopyridine (DMAP)-BH⋅ was selected as a representative of LBRs, and its reactions with six monochloro-substituted substrates, including three methyl chlorobenzoates and three chlorinated acetanilides were studied in experiments and theoretical calculations.
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