Catalytic 1,2-Regioselective Dearomatization of N-Heteroaromatics via a Hydroboration

Heng Liu; Maxim Khononov; Moris S. Eisen

doi:10.1021/acscatal.8b00074

Catalytic 1,2-Regioselective Dearomatization of N-Heteroaromatics via a Hydroboration

Heng Liu, Maxim Khononov, Moris S. Eisen^*

^*Corresponding author for this work

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

50 Scopus citations

Abstract

The thorium methyl and hydride complex (C₅Me₅)₂ThMe₂ and [(C₅Me₅)₂Th(H)(μ-H)]₂ catalyzed highly 1,2-regioselective dearomatization of pyridines via a hydroboration process is reported herein. Twelve different kinds of meta- and para-substituted pyridines are applicable to this reaction, giving the corresponding N-boryl-1,2-dihydropyridine products in high yields. Other N-heteroaromatic compounds, such as benzo-fused N-heterocycles, pyrazines, pyrimidines, 1,3,5-triazine, and benzothiazole, were also found to be hydroborated with high chemoselectivity. Kinetics including isotope effect studies revealed a first-order dependence on the concentration of catalyst, pyridine, and pinacolborane, with release of the dearomatized final product as the rate-determining step. A plausible mechanism is proposed on the basis of stoichiometric reactions and kinetic studies.

Original language	English
Pages (from-to)	3673-3677
Number of pages	5
Journal	ACS Catalysis
Volume	8
Issue number	4
DOIs	https://doi.org/10.1021/acscatal.8b00074
State	Published - 6 Apr 2018
Externally published	Yes

Keywords

1,2-regioselective
N-heteroaromatic
dearomatization
pyridine
thorium

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10.1021/acscatal.8b00074

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title = "Catalytic 1,2-Regioselective Dearomatization of N-Heteroaromatics via a Hydroboration",

abstract = "The thorium methyl and hydride complex (C5Me5)2ThMe2 and [(C5Me5)2Th(H)(μ-H)]2 catalyzed highly 1,2-regioselective dearomatization of pyridines via a hydroboration process is reported herein. Twelve different kinds of meta- and para-substituted pyridines are applicable to this reaction, giving the corresponding N-boryl-1,2-dihydropyridine products in high yields. Other N-heteroaromatic compounds, such as benzo-fused N-heterocycles, pyrazines, pyrimidines, 1,3,5-triazine, and benzothiazole, were also found to be hydroborated with high chemoselectivity. Kinetics including isotope effect studies revealed a first-order dependence on the concentration of catalyst, pyridine, and pinacolborane, with release of the dearomatized final product as the rate-determining step. A plausible mechanism is proposed on the basis of stoichiometric reactions and kinetic studies.",

keywords = "1,2-regioselective, N-heteroaromatic, dearomatization, pyridine, thorium",

author = "Heng Liu and Maxim Khononov and Eisen, {Moris S.}",

note = "Publisher Copyright: {\textcopyright} 2018 American Chemical Society.",

year = "2018",

month = apr,

day = "6",

doi = "10.1021/acscatal.8b00074",

language = "英语",

volume = "8",

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T1 - Catalytic 1,2-Regioselective Dearomatization of N-Heteroaromatics via a Hydroboration

AU - Liu, Heng

AU - Khononov, Maxim

AU - Eisen, Moris S.

PY - 2018/4/6

Y1 - 2018/4/6

N2 - The thorium methyl and hydride complex (C5Me5)2ThMe2 and [(C5Me5)2Th(H)(μ-H)]2 catalyzed highly 1,2-regioselective dearomatization of pyridines via a hydroboration process is reported herein. Twelve different kinds of meta- and para-substituted pyridines are applicable to this reaction, giving the corresponding N-boryl-1,2-dihydropyridine products in high yields. Other N-heteroaromatic compounds, such as benzo-fused N-heterocycles, pyrazines, pyrimidines, 1,3,5-triazine, and benzothiazole, were also found to be hydroborated with high chemoselectivity. Kinetics including isotope effect studies revealed a first-order dependence on the concentration of catalyst, pyridine, and pinacolborane, with release of the dearomatized final product as the rate-determining step. A plausible mechanism is proposed on the basis of stoichiometric reactions and kinetic studies.

AB - The thorium methyl and hydride complex (C5Me5)2ThMe2 and [(C5Me5)2Th(H)(μ-H)]2 catalyzed highly 1,2-regioselective dearomatization of pyridines via a hydroboration process is reported herein. Twelve different kinds of meta- and para-substituted pyridines are applicable to this reaction, giving the corresponding N-boryl-1,2-dihydropyridine products in high yields. Other N-heteroaromatic compounds, such as benzo-fused N-heterocycles, pyrazines, pyrimidines, 1,3,5-triazine, and benzothiazole, were also found to be hydroborated with high chemoselectivity. Kinetics including isotope effect studies revealed a first-order dependence on the concentration of catalyst, pyridine, and pinacolborane, with release of the dearomatized final product as the rate-determining step. A plausible mechanism is proposed on the basis of stoichiometric reactions and kinetic studies.

KW - 1,2-regioselective

KW - N-heteroaromatic

KW - dearomatization

KW - pyridine

KW - thorium

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U2 - 10.1021/acscatal.8b00074

DO - 10.1021/acscatal.8b00074

M3 - 文章

AN - SCOPUS:85045086379

SN - 2155-5435

VL - 8

SP - 3673

EP - 3677

JO - ACS Catalysis

JF - ACS Catalysis

IS - 4

ER -

Catalytic 1,2-Regioselective Dearomatization of N-Heteroaromatics via a Hydroboration

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Keywords

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