Stereoselective Bromoboration of Acetylene with Boron
Tribromide: Preparation and Cross-Coupling Reactions of
(Z)-Bromovinylboronates

J 2020

Stereoselective Bromoboration of Acetylene with Boron Tribromide: Preparation and Cross-Coupling Reactions of (Z)-Bromovinylboronates

POLÁŠEK, Jan; Jan PACIOREK; Jakub STOŠEK; Hugo SEMRÁD; Markéta MUNZAROVÁ et al.

Basic information

Original name

Stereoselective Bromoboration of Acetylene with Boron Tribromide: Preparation and Cross-Coupling Reactions of (Z)-Bromovinylboronates

Authors

POLÁŠEK, Jan; Jan PACIOREK; Jakub STOŠEK; Hugo SEMRÁD ; Markéta MUNZAROVÁ and Ctibor MAZAL

Edition

The Journal of Organic Chemistry, Washington, D.C. American Chemical Society, 2020, 0022-3263

Other information

Language

English

Type of outcome

Article in a journal

Field of Study

10401 Organic chemistry

Country of publisher

United States of America

Confidentiality degree

is not subject to a state or trade secret

References:

URL

Impact factor

Impact factor: 4.354

RIV identification code

RIV/00216224:14310/20:00115701

Organization unit

Faculty of Science

DOI

https://doi.org/10.1021/acs.joc.0c00341

UT WoS

000538764000016

EID Scopus

2-s2.0-85085703219

Keywords in English

HALOBORATION REACTIONS; UNSATURATED-COMPOUNDS; BUILDING-BLOCKS; HYDROBORATION; ISOMERIZATION; CYCLIZATION; CATALYST; ALKYNES; ROUTE

Abstract

In the original language

The mechanism of acetylene bromoboration in neat boron tribromide was studied carefully by means of experiment and theory. Besides the syn-addition mechanism through a four-center transition state, radical and polar anti-addition mechanisms are postulated, both triggered by HBr, which is evidenced also to take part in the Z/E isomerization of the product. The proposed mechanism is well supported by ab initio calculations at the MP2/6-31+G* level with Ahlrichs’ SVP all-electron basis for Br. Implicit solvation in CH2Cl2 has been included using the PCM and/or SMD continuum solvent models. Comparative case studies have been performed involving the B3LYP/6-31+G* with Ahlrichs’ SVP for Br and MP2/Def2TZVPP levels. The mechanistic studies resulted in development of a procedure for stereoselective bromoboration of acetylene yielding E/Z mixtures of dibromo(bromovinyl)borane with the Z-isomer as a major product (up to 85%). Transformation to the corresponding pinacol and neopentyl glycol boronates and stereoselective decomposition of their E-isomer provided pure (Z)-(2-bromovinyl)boronates in 57–60% overall yield. Their reactivity in a Negishi cross-coupling reaction was tested. An example of the one-pot reaction sequence of Negishi and Suzuki–Miyaura cross-couplings for synthesis of combretastatin A4 is also presented.

Links

LM2015047, research and development project

Name: Česká národní infrastruktura pro biologická data (Acronym: ELIXIR-CZ)

Investor: Ministry of Education, Youth and Sports of the CR, Czech National Infrastructure for Biological Data

LM2018140, research and development project

Name: e-Infrastruktura CZ (Acronym: e-INFRA CZ)

Investor: Ministry of Education, Youth and Sports of the CR

MUNI/A/1313/2018, interní kód MU

Name: Nové syntetické metody pro molekulární, supramolekulární a nanostrukturní systémy (Acronym: NOSYME)

Investor: Masaryk University, Category A

MUNI/A/1424/2019, interní kód MU

Name: Vývoj metod a instrumentace pro analýzu biologicky významných látek 2020

Investor: Masaryk University, Category A

Cite

POLÁŠEK, Jan; Jan PACIOREK; Jakub STOŠEK; Hugo SEMRÁD; Markéta MUNZAROVÁ and Ctibor MAZAL. Stereoselective Bromoboration of Acetylene with Boron Tribromide: Preparation and Cross-Coupling Reactions of (Z)-Bromovinylboronates. The Journal of Organic Chemistry. Washington, D.C.: American Chemical Society, 2020, vol. 85, No 11, p. 6992-7000. ISSN 0022-3263. Available from: https://doi.org/10.1021/acs.joc.0c00341.

@article{1658581,
   author = {Polášek, Jan and Paciorek, Jan and Stošek, Jakub and Semrád, Hugo and Munzarová, Markéta and Mazal, Ctibor},
   article_location = {Washington, D.C.},
   article_number = {11},
   doi = {https://doi.org/10.1021/acs.joc.0c00341},
   keywords = {HALOBORATION REACTIONS; UNSATURATED-COMPOUNDS; BUILDING-BLOCKS; HYDROBORATION; ISOMERIZATION; CYCLIZATION; CATALYST; ALKYNES; ROUTE},
   language = {eng},
   issn = {0022-3263},
   journal = {The Journal of Organic Chemistry},
   title = {Stereoselective Bromoboration of Acetylene with Boron Tribromide: Preparation and Cross-Coupling Reactions of (Z)-Bromovinylboronates},
   url = {https://pubs.acs.org/doi/10.1021/acs.joc.0c00341},
   volume = {85},
   year = {2020}
}

TY  - JOUR
ID  - 1658581
AU  - Polášek, Jan - Paciorek, Jan - Stošek, Jakub - Semrád, Hugo - Munzarová, Markéta - Mazal, Ctibor
PY  - 2020
TI  - Stereoselective Bromoboration of Acetylene with Boron Tribromide: Preparation and Cross-Coupling Reactions of (Z)-Bromovinylboronates
JF  - The Journal of Organic Chemistry
VL  - 85
IS  - 11
SP  - 6992-7000
EP  - 6992-7000
PB  - American Chemical Society
SN  - 00223263
KW  - HALOBORATION REACTIONS
KW  - UNSATURATED-COMPOUNDS
KW  - BUILDING-BLOCKS
KW  - HYDROBORATION
KW  - ISOMERIZATION
KW  - CYCLIZATION
KW  - CATALYST
KW  - ALKYNES
KW  - ROUTE
UR  - https://pubs.acs.org/doi/10.1021/acs.joc.0c00341
L2  - https://pubs.acs.org/doi/10.1021/acs.joc.0c00341
N2  - The mechanism of acetylene bromoboration in neat boron tribromide was studied carefully by means of experiment and theory. Besides the syn-addition mechanism through a four-center transition state, radical and polar anti-addition mechanisms are postulated, both triggered by HBr, which is evidenced also to take part in the Z/E isomerization of the product. The proposed mechanism is well supported by ab initio calculations at the MP2/6-31+G* level with Ahlrichs’ SVP all-electron basis for Br. Implicit solvation in CH2Cl2 has been included using the PCM and/or SMD continuum solvent models. Comparative case studies have been performed involving the B3LYP/6-31+G* with Ahlrichs’ SVP for Br and MP2/Def2TZVPP levels. The mechanistic studies resulted in development of a procedure for stereoselective bromoboration of acetylene yielding E/Z mixtures of dibromo(bromovinyl)borane with the Z-isomer as a major product (up to 85%). Transformation to the corresponding pinacol and neopentyl glycol boronates and stereoselective decomposition of their E-isomer provided pure (Z)-(2-bromovinyl)boronates in 57–60% overall yield. Their reactivity in a Negishi cross-coupling reaction was tested. An example of the one-pot reaction sequence of Negishi and Suzuki–Miyaura cross-couplings for synthesis of combretastatin A4 is also presented.
ER  -

POLÁŠEK, Jan; Jan PACIOREK; Jakub STOŠEK; Hugo SEMRÁD; Markéta MUNZAROVÁ and Ctibor MAZAL. Stereoselective Bromoboration of Acetylene with Boron Tribromide: Preparation and Cross-Coupling Reactions of (Z)-Bromovinylboronates. \textit{The Journal of Organic Chemistry}. Washington, D.C.: American Chemical Society, 2020, vol.~85, No~11, p.~6992-7000. ISSN~0022-3263. Available from: https://doi.org/10.1021/acs.joc.0c00341.

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