Cobalt-Catalyzed Asymmetric Sequential Hydroboration/Isomerization/Hydroboration of 2-Aryl Vinylcyclopropanes

Chenhui Chen; Hongliang Wang; Tongtong Li; Dongpo Lu; Jiajing Li; Xie Zhang; Xin Hong; Zhan Lu

doi:10.1002/anie.202205619

Cobalt-Catalyzed Asymmetric Sequential Hydroboration/Isomerization/Hydroboration of 2-Aryl Vinylcyclopropanes

Angew Chem Int Ed Engl. 2022 Jul 25;61(30):e202205619. doi: 10.1002/anie.202205619. Epub 2022 Jun 10.

Authors

Chenhui Chen¹, Hongliang Wang^{1

2}, Tongtong Li¹, Dongpo Lu¹, Jiajing Li¹, Xie Zhang¹, Xin Hong^{1

3

4

5}, Zhan Lu^{1

6

7}

Affiliations

¹ Department of Chemistry, Zhejiang University, Hangzhou, 310058, China.
² School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, China.
³ Center of Chemistry for Frontier Technologies, State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, China.
⁴ Beijing National Laboratory for Molecular Sciences, Zhongguancun North First Street NO. 2, Beijing, 100190, China.
⁵ Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, School of Science, Westlake University, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China.
⁶ College of Chemistry, Zhengzhou University, Zhengzhou, 450001, China.
⁷ Center of Chemistry for Frontier Technologies, Zhejiang University, Hangzhou, 310027, China.

PMID: 35607762
DOI: 10.1002/anie.202205619

Abstract

A cobalt-catalyzed asymmetric sequential hydroboration/isomerization/hydroboration of 2-aryl vinylcyclopropanes was for the first time reported for the preparation of valuable chiral 1,5-bis(boronates) in good yields with excellent enantioselectivity via asymmetric sequential isomerization/hydroboration of a trisubstituted alkene intermediate. The reaction was carried out smoothly and this protocol was used for asymmetric syntheses of (-)-preclamol in gram-scale. The two primary C^(sp3) -B bonds in chiral 1,5-bis(boronates) could be distinguished in iterative Suzuki-Miyaura cross-coupling reaction, delivering chiral 1,2,5-triaryl alkanes with excellent enantioselectivity. Based on experimental and computational studies, a cobalt-hydride species was proposed as the active intermediate in hydroboration, isomerization, and second hydroboration reactions.

Keywords: Chiral Boronates; Cobalt; Hydroboration; Iterative Coupling; Vinylcyclopropanes.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Alkenes* / chemistry
Catalysis
Cobalt* / chemistry
Isomerism
Stereoisomerism

Substances

Alkenes
Cobalt