Photoinduced oxidation of benzylic boronic esters to ketones/aldehydes <i>via</i> α-borylalkyl radicals

Wang, Zhijun; Wei, Lanfeng; Liu, Jichang; Yu, Wu; Xu, Liang

doi:10.1039/d2qo01457b

Cited by 8 publications

(2 citation statements)

References 37 publications

(17 reference statements)

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“…Previously, we discovered that a catalytic amount of TBATB was used to achieve the efficient conversion of alkyl pinacol esters into the corresponding aryl ketones. 16 Similarly, we attempted to utilize Br˙ generated by visible light excitation of TBATB to achieve hydrogen transfer at the α-C(sp 3 ) position of THF and complete the Minisci-type reaction between THF and N-heterocycles (Scheme 1c).…”

Section: Introductionmentioning

confidence: 99%

A visible-light-induced bromine radical initiates direct C–H alkylation of heteroaromatics

Cao,

Wei,

Yang

et al. 2024

Org. Biomol. Chem.

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Section: Introductionmentioning

confidence: 99%

A visible-light-induced bromine radical initiates direct C–H alkylation of heteroaromatics

Cao,

Wei,

Yang

et al. 2024

Org. Biomol. Chem.

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“…This outcome was not surprising, given the radical mechanism of Wohl–Ziegler bromination . The π-donation between the radical and the vacant p orbital of the boron atom has been widely documented. , However, this stabilization effect must be subtle compared with that of an aryl group, because geminal bis(boronates) were much less reactive. Indeed, in another competition experiment, 43 and ethylbenzene exhibited almost identical reactivity (35% and 32%, respectively).…”

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confidence: 99%

Construction of α-Halogenated Boronic Esters via Visible Light-Induced C–H Bromination

Gao,

Li,

et al. 2023

J. Org. Chem.

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α-Halogenated boronic esters are versatile building blocks that can be diversified into a wide variety of polyfunctionalized molecules. However, their synthetic potential has been hampered by limited preparation methods. Herein, we report a visible light-induced C−H bromination reaction of readily available benzyl boronic esters. This method features high yields, mild conditions, simple operation, and good functional group tolerance. The analogous chlorides and iodides can be accessed via Finkelstein reaction. Synthesis of halogenated geminal diborons has also been demonstrated.

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Palladium‐Catalyzed Cascade Heck Coupling and Allylboration of Iododiboron Compounds via Diboryl Radicals

Wei,

Xie,

Liu

et al. 2024

Angewandte Chemie

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Geminal bis(boronates) are versatile synthetic building blocks in organic chemistry. The fact that they predominantly serve as nucleophiles in the previous reports, however, has restrained their synthetic potential. Herein we disclose the ambiphilic reactivity of α‐halogenated geminal bis(boronates), of which the first catalytic utilization was accomplished by merging a formal Heck cross‐coupling with a highly diastereoselective allylboration of aldehydes or imines, providing a new avenue for rapid assembly of polyfunctionalized boron‐containing compounds. We demonstrated that this cascade reaction is highly efficient and compatible with various functional groups, and a wide range of heterocycles. In contrast to a classical Pd(0/II) scenario, mechanistic experiments and DFT calculations have provided strong evidence for a catalytic cycle involving Pd(I)/diboryl carbon radical intermediates.

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Photoinduced oxidation of benzylic boronic esters to ketones/aldehydes via α-borylalkyl radicals

Abstract: A method for direct oxidation of boronic esters to the carbonyl groups has been established herein. Under the irradiation of visible light and O2 atmosphere, ketones and aldehydes can be...

Cited by 8 publications

References 37 publications

A visible-light-induced bromine radical initiates direct C–H alkylation of heteroaromatics

A visible-light-induced bromine radical initiates direct C–H alkylation of heteroaromatics

Construction of α-Halogenated Boronic Esters via Visible Light-Induced C–H Bromination

Palladium‐Catalyzed Cascade Heck Coupling and Allylboration of Iododiboron Compounds via Diboryl Radicals

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