Cobalt-Catalyzed Benzylic Borylation: Enabling Polyborylation and Functionalization of Remote, Unactivated C(sp3)-H Bonds

W. Neil Palmer; Jennifer V. Obligacion; Iraklis Pappas; Paul J. Chirik

doi:10.1021/jacs.5b12249

Cobalt-Catalyzed Benzylic Borylation: Enabling Polyborylation and Functionalization of Remote, Unactivated C(sp³)-H Bonds

W. Neil Palmer, Jennifer V. Obligacion, Iraklis Pappas, Paul J. Chirik

Chemistry

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

150 Scopus citations

Abstract

Cobalt dialkyl and bis(carboxylate) complexes bearing α-diimine ligands have been synthesized and demonstrated as active for the C(sp³)-H borylation of a range of substituted alkyl arenes using B₂Pin₂ (Pin = pinacolate) as the boron source. At longer reaction times, rare examples of polyborylation were observed, and in the case of toluene, all three benzylic C-H positions were functionalized. Coupling benzylic C-H activation with alkyl isomerization enabled a base-metal-catalyzed method for the borylation of remote, unactivated C(sp³)-H bonds.

Original language	English (US)
Pages (from-to)	766-769
Number of pages	4
Journal	Journal of the American Chemical Society
Volume	138
Issue number	3
DOIs	https://doi.org/10.1021/jacs.5b12249
State	Published - Jan 27 2016

All Science Journal Classification (ASJC) codes

Catalysis
Chemistry(all)
Biochemistry
Colloid and Surface Chemistry

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title = "Cobalt-Catalyzed Benzylic Borylation: Enabling Polyborylation and Functionalization of Remote, Unactivated C(sp3)-H Bonds",

abstract = "Cobalt dialkyl and bis(carboxylate) complexes bearing α-diimine ligands have been synthesized and demonstrated as active for the C(sp3)-H borylation of a range of substituted alkyl arenes using B2Pin2 (Pin = pinacolate) as the boron source. At longer reaction times, rare examples of polyborylation were observed, and in the case of toluene, all three benzylic C-H positions were functionalized. Coupling benzylic C-H activation with alkyl isomerization enabled a base-metal-catalyzed method for the borylation of remote, unactivated C(sp3)-H bonds.",

author = "Palmer, {W. Neil} and Obligacion, {Jennifer V.} and Iraklis Pappas and Chirik, {Paul J.}",

note = "Funding Information: W.N.P. acknowledges the National Science Foundation (CHE-1265988) for financial support. J.V.O. acknowledges the 2014-2015 Bristol-Myers Squibb Graduate Fellowship in Synthetic Organic Chemistry and the Paul Maeder {\textquoteright}75 Fund for Energy and the Environment through the Andlinger Center. We thank Allychem for a generous gift of B2Pin2. Publisher Copyright: {\textcopyright} 2015 American Chemical Society.",

year = "2016",

month = jan,

day = "27",

doi = "10.1021/jacs.5b12249",

language = "English (US)",

volume = "138",

pages = "766--769",

journal = "Journal of the American Chemical Society",

issn = "0002-7863",

publisher = "American Chemical Society",

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TY - JOUR

T1 - Cobalt-Catalyzed Benzylic Borylation

T2 - Enabling Polyborylation and Functionalization of Remote, Unactivated C(sp3)-H Bonds

AU - Palmer, W. Neil

AU - Obligacion, Jennifer V.

AU - Pappas, Iraklis

AU - Chirik, Paul J.

N1 - Funding Information: W.N.P. acknowledges the National Science Foundation (CHE-1265988) for financial support. J.V.O. acknowledges the 2014-2015 Bristol-Myers Squibb Graduate Fellowship in Synthetic Organic Chemistry and the Paul Maeder ’75 Fund for Energy and the Environment through the Andlinger Center. We thank Allychem for a generous gift of B2Pin2. Publisher Copyright: © 2015 American Chemical Society.

PY - 2016/1/27

Y1 - 2016/1/27

N2 - Cobalt dialkyl and bis(carboxylate) complexes bearing α-diimine ligands have been synthesized and demonstrated as active for the C(sp3)-H borylation of a range of substituted alkyl arenes using B2Pin2 (Pin = pinacolate) as the boron source. At longer reaction times, rare examples of polyborylation were observed, and in the case of toluene, all three benzylic C-H positions were functionalized. Coupling benzylic C-H activation with alkyl isomerization enabled a base-metal-catalyzed method for the borylation of remote, unactivated C(sp3)-H bonds.

AB - Cobalt dialkyl and bis(carboxylate) complexes bearing α-diimine ligands have been synthesized and demonstrated as active for the C(sp3)-H borylation of a range of substituted alkyl arenes using B2Pin2 (Pin = pinacolate) as the boron source. At longer reaction times, rare examples of polyborylation were observed, and in the case of toluene, all three benzylic C-H positions were functionalized. Coupling benzylic C-H activation with alkyl isomerization enabled a base-metal-catalyzed method for the borylation of remote, unactivated C(sp3)-H bonds.

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Cobalt-Catalyzed Benzylic Borylation: Enabling Polyborylation and Functionalization of Remote, Unactivated C(sp³)-H Bonds

Abstract

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