A chemoselective polarity-mismatched photocatalytic C(sp3)–C(sp2) cross-coupling enabled by synergistic boron activation

Jeremy Brals; Thomas McGuire; Allan J. B. Watson

doi:10.1002/anie.202310462

A chemoselective polarity-mismatched photocatalytic C(sp³)–C(sp²) cross-coupling enabled by synergistic boron activation

Jeremy Brals, Thomas McGuire, Allan J. B. Watson^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

Abstract

We report the development of a C(sp³)–C(sp²) coupling reaction using styrene boronic acids and redox-active esters under photoredox catalysis. The reaction proceeds through an unusual polarity-mismatched radical addition mechanism that is orthogonal to established processes. Synergistic activation of the radical precursor and organoboron are critical mechanistic events. Activation of an N-hydroxyphthalimide (NHPI) ester by coordination to boron enables electron transfer, with decomposition leading to a nucleofuge rebound, activating the organoboron to radical addition. The unique mechanism enables chemoselective coupling of styrene boronic acids in the presence of other alkene radical acceptors. The scope and limitations of the reaction, and a detailed mechanistic investigation are presented.

Original language	English
Article number	e202310462
Number of pages	9
Journal	Angewandte Chemie International Edition
Volume	62
Issue number	42
Early online date	13 Sept 2023
DOIs	https://doi.org/10.1002/anie.202310462
Publication status	Published - 9 Oct 2023

Keywords

Boron
Chemoselectivity
Cross-coupling
Crossover
Photosynthesis

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10.1002/anie.202310462Licence: CC BY

Brals_2023_ACIE_Chemoselectivepolarity_CCBY
Copyright © 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Final published version, 8.46 MBLicence: CC BY

Cite this

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title = "A chemoselective polarity-mismatched photocatalytic C(sp3)–C(sp2) cross-coupling enabled by synergistic boron activation",

abstract = "We report the development of a C(sp3)–C(sp2) coupling reaction using styrene boronic acids and redox-active esters under photoredox catalysis. The reaction proceeds through an unusual polarity-mismatched radical addition mechanism that is orthogonal to established processes. Synergistic activation of the radical precursor and organoboron are critical mechanistic events. Activation of an N-hydroxyphthalimide (NHPI) ester by coordination to boron enables electron transfer, with decomposition leading to a nucleofuge rebound, activating the organoboron to radical addition. The unique mechanism enables chemoselective coupling of styrene boronic acids in the presence of other alkene radical acceptors. The scope and limitations of the reaction, and a detailed mechanistic investigation are presented.",

keywords = "Boron, Chemoselectivity, Cross-coupling, Crossover, Photosynthesis",

author = "Jeremy Brals and Thomas McGuire and Watson, {Allan J. B.}",

note = "Funding: J.B. thanks AstraZeneca and the Engineering and Physical Sciences Research Council (EPSRC) for a PhD studentship. A.J.B.W. thanks the Leverhulme Trust for a Research Fellowship (RF-2022-014) and the EPSRC Programme Grant “Boron: Beyond the Reagent” (EP/W007517) for support.",

year = "2023",

month = oct,

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doi = "10.1002/anie.202310462",

language = "English",

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journal = "Angewandte Chemie International Edition",

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T1 - A chemoselective polarity-mismatched photocatalytic C(sp3)–C(sp2) cross-coupling enabled by synergistic boron activation

AU - Brals, Jeremy

AU - McGuire, Thomas

AU - Watson, Allan J. B.

N1 - Funding: J.B. thanks AstraZeneca and the Engineering and Physical Sciences Research Council (EPSRC) for a PhD studentship. A.J.B.W. thanks the Leverhulme Trust for a Research Fellowship (RF-2022-014) and the EPSRC Programme Grant “Boron: Beyond the Reagent” (EP/W007517) for support.

PY - 2023/10/9

Y1 - 2023/10/9

N2 - We report the development of a C(sp3)–C(sp2) coupling reaction using styrene boronic acids and redox-active esters under photoredox catalysis. The reaction proceeds through an unusual polarity-mismatched radical addition mechanism that is orthogonal to established processes. Synergistic activation of the radical precursor and organoboron are critical mechanistic events. Activation of an N-hydroxyphthalimide (NHPI) ester by coordination to boron enables electron transfer, with decomposition leading to a nucleofuge rebound, activating the organoboron to radical addition. The unique mechanism enables chemoselective coupling of styrene boronic acids in the presence of other alkene radical acceptors. The scope and limitations of the reaction, and a detailed mechanistic investigation are presented.

AB - We report the development of a C(sp3)–C(sp2) coupling reaction using styrene boronic acids and redox-active esters under photoredox catalysis. The reaction proceeds through an unusual polarity-mismatched radical addition mechanism that is orthogonal to established processes. Synergistic activation of the radical precursor and organoboron are critical mechanistic events. Activation of an N-hydroxyphthalimide (NHPI) ester by coordination to boron enables electron transfer, with decomposition leading to a nucleofuge rebound, activating the organoboron to radical addition. The unique mechanism enables chemoselective coupling of styrene boronic acids in the presence of other alkene radical acceptors. The scope and limitations of the reaction, and a detailed mechanistic investigation are presented.

KW - Boron

KW - Chemoselectivity

KW - Cross-coupling

KW - Crossover

KW - Photosynthesis

UR - https://doi.org/10.26434/chemrxiv-2023-m5d6s

U2 - 10.1002/anie.202310462

DO - 10.1002/anie.202310462

M3 - Article

SN - 1433-7851

VL - 62

JO - Angewandte Chemie International Edition

JF - Angewandte Chemie International Edition

IS - 42

M1 - e202310462

ER -

A chemoselective polarity-mismatched photocatalytic C(sp³)–C(sp²) cross-coupling enabled by synergistic boron activation

Abstract

Keywords

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Fingerprint

Allan Watson Programme Grant: Boron: Beyond the Reagent

A biochemical boron tagging stategy: A biochemical boron tagging strategy for biomolecule visualisation and profiling

Photocatalytic C(sp3)–C(sp2) radical-polar crossover cross-coupling of styrenyl boronic acids (thesis data)

Dataset underpinning "A chemoselective polarity-mismatched photocatalytic C(sp3)–C(sp2) cross-coupling enabled by synergistic boron activation"

Cite this

A chemoselective polarity-mismatched photocatalytic C(sp3)–C(sp2) cross-coupling enabled by synergistic boron activation

Abstract

Keywords

Access to Document

Other files and links

Fingerprint

Projects

Allan Watson Programme Grant: Boron: Beyond the Reagent

A biochemical boron tagging stategy: A biochemical boron tagging strategy for biomolecule visualisation and profiling

Datasets

Photocatalytic C(sp3)–C(sp2) radical-polar crossover cross-coupling of styrenyl boronic acids (thesis data)

Dataset underpinning "A chemoselective polarity-mismatched photocatalytic C(sp3)–C(sp2) cross-coupling enabled by synergistic boron activation"

Cite this

A chemoselective polarity-mismatched photocatalytic C(sp³)–C(sp²) cross-coupling enabled by synergistic boron activation