Alkoxide-Promoted Selective Hydroboration of N-Heteroarenes: Pivotal Roles of in situ Generated BH                         3                          in the Dearomatization Process

Eunchan Jeong; Joon Heo; Sehoon Park; Sukbok Chang

doi:10.1002/chem.201901214

Alkoxide-Promoted Selective Hydroboration of N-Heteroarenes: Pivotal Roles of in situ Generated BH ₃ in the Dearomatization Process

Eunchan Jeong, Joon Heo, Sehoon Park^*, Sukbok Chang

^*Corresponding author for this work

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

41 Scopus citations

Abstract

While numerous organo(metallic)catalyst systems were documented for dearomative hydroboration of N-aromatics, alkoxide base catalysts have not been disclosed thus far. Described herein is the first example of alkoxide-catalyzed hydroboration of N-heteroaromatics including pyridines, providing a broad range of reduced N-heterocycles with high efficiency and selectivity. Mechanistic studies revealed an unprecedented counterintuitive dearomatization pathway, in which 1) pyridine-BH ₃ adducts undergo a hydride attack by alkoxyborohydrides, 2) in situ generated BH ₃ serves as a catalytic promoter, and 3) 1,4-dihydropyridyl borohydride is in a predominant resting state.

Original language	English
Pages (from-to)	6320-6325
Number of pages	6
Journal	Chemistry - A European Journal
Volume	25
Issue number	25
DOIs	https://doi.org/10.1002/chem.201901214
State	Published - 2 May 2019
Externally published	Yes

Keywords

N-heteroarenes
alkali base catalyst
dearomatization
hydroboration
ionic mechanism

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10.1002/chem.201901214

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title = "Alkoxide-Promoted Selective Hydroboration of N-Heteroarenes: Pivotal Roles of in situ Generated BH 3 in the Dearomatization Process",

abstract = " While numerous organo(metallic)catalyst systems were documented for dearomative hydroboration of N-aromatics, alkoxide base catalysts have not been disclosed thus far. Described herein is the first example of alkoxide-catalyzed hydroboration of N-heteroaromatics including pyridines, providing a broad range of reduced N-heterocycles with high efficiency and selectivity. Mechanistic studies revealed an unprecedented counterintuitive dearomatization pathway, in which 1) pyridine-BH 3 adducts undergo a hydride attack by alkoxyborohydrides, 2) in situ generated BH 3 serves as a catalytic promoter, and 3) 1,4-dihydropyridyl borohydride is in a predominant resting state.",

keywords = "N-heteroarenes, alkali base catalyst, dearomatization, hydroboration, ionic mechanism",

author = "Eunchan Jeong and Joon Heo and Sehoon Park and Sukbok Chang",

note = "Publisher Copyright: {\textcopyright} 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim",

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month = may,

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doi = "10.1002/chem.201901214",

language = "英语",

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Alkoxide-Promoted Selective Hydroboration of N-Heteroarenes: Pivotal Roles of in situ Generated BH ₃ in the Dearomatization Process. / Jeong, Eunchan; Heo, Joon; Park, Sehoon et al.
In: Chemistry - A European Journal, Vol. 25, No. 25, 02.05.2019, p. 6320-6325.

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

TY - JOUR

T1 - Alkoxide-Promoted Selective Hydroboration of N-Heteroarenes

T2 - Pivotal Roles of in situ Generated BH 3 in the Dearomatization Process

AU - Jeong, Eunchan

AU - Heo, Joon

AU - Park, Sehoon

AU - Chang, Sukbok

PY - 2019/5/2

Y1 - 2019/5/2

N2 - While numerous organo(metallic)catalyst systems were documented for dearomative hydroboration of N-aromatics, alkoxide base catalysts have not been disclosed thus far. Described herein is the first example of alkoxide-catalyzed hydroboration of N-heteroaromatics including pyridines, providing a broad range of reduced N-heterocycles with high efficiency and selectivity. Mechanistic studies revealed an unprecedented counterintuitive dearomatization pathway, in which 1) pyridine-BH 3 adducts undergo a hydride attack by alkoxyborohydrides, 2) in situ generated BH 3 serves as a catalytic promoter, and 3) 1,4-dihydropyridyl borohydride is in a predominant resting state.

AB - While numerous organo(metallic)catalyst systems were documented for dearomative hydroboration of N-aromatics, alkoxide base catalysts have not been disclosed thus far. Described herein is the first example of alkoxide-catalyzed hydroboration of N-heteroaromatics including pyridines, providing a broad range of reduced N-heterocycles with high efficiency and selectivity. Mechanistic studies revealed an unprecedented counterintuitive dearomatization pathway, in which 1) pyridine-BH 3 adducts undergo a hydride attack by alkoxyborohydrides, 2) in situ generated BH 3 serves as a catalytic promoter, and 3) 1,4-dihydropyridyl borohydride is in a predominant resting state.

KW - N-heteroarenes

KW - alkali base catalyst

KW - dearomatization

KW - hydroboration

KW - ionic mechanism

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U2 - 10.1002/chem.201901214

DO - 10.1002/chem.201901214

M3 - 文章

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AN - SCOPUS:85064246600

SN - 0947-6539

VL - 25

SP - 6320

EP - 6325

JO - Chemistry - A European Journal

JF - Chemistry - A European Journal

IS - 25

ER -

Alkoxide-Promoted Selective Hydroboration of N-Heteroarenes: Pivotal Roles of in situ Generated BH ₃ in the Dearomatization Process

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Keywords

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