A Novel Synthesis of Halogenated <i>gem</i>-Diboron Reagents

Fang, Tongchang; Xu, Liangxuan; Qin, Yucheng; Jiang, Nanquan; Liu, Chao

doi:10.6023/cjoc202207030

Cited by 19 publications

(4 citation statements)

References 47 publications

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“…Next, we proved that our strategy is not only suitable for the synthesis of internal gem ‐bis(boronates) but can also serve as a general method for the terminal analogues. Using diborylmethyl chloride ( 53 ), which was independently developed by Cho [17a] and Liu, [17b] we could access a wide variety of 1,1‐diborylalkanes ( 54 – 62 ), some of which were previously tricky to synthesize. Notably, with less hindered substrate, tertiary Grignard reagent could readily react to provide product 56 in 97 % yield.…”

Section: Resultsmentioning

confidence: 99%

A General Method to Access Sterically Encumbered Geminal Bis(boronates) via Formal Umpolung Transformation of Terminal Diboron Compounds

Ning,

Wei,

Chen

et al. 2023

Angewandte Chemie

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General methods for the preparation of geminal bis(boronates) are of great interest due to their widespread applications in organic synthesis. While the terminal gem‐diboron compounds are readily accessible, the construction of the sterically encumbered, internal analogues has remained a prominent challenge. Herein, we report a formal umpolung strategy to access these valuable building blocks. The readily available 1,1‐diborylalkanes were first converted into the corresponding α‐halogenated derivatives, which then serve as electrophilic components, undergoing a formal substitution with a diverse array of nucleophiles to form a series of C−C, C−O, C−S, and C−N bonds. This protocol features good tolerance to steric hindrance and a wide variety of functional groups and heterocycles. Notably, this strategy can also be extended to the synthesis of diaryl and terminal gem‐diboron compounds, therefore providing a general approach to various types of geminal bis(boronates).

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Section: Resultsmentioning

confidence: 99%

A General Method to Access Sterically Encumbered Geminal Bis(boronates) via Formal Umpolung Transformation of Terminal Diboron Compounds

Ning,

Wei,

Chen

et al. 2023

Angewandte Chemie

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“…Subsequent bromine or iodine substituted halodiboryl-methanes can be prepared by halide exchange with sodium bromide and sodium iodide (Scheme 16b). [38] Also alkyl-substituted gem-dichloro compounds serve to be transformed into the corresponding gemhalodiboryl alkanes with tetrasubstituted alkanes.…”

Section: α-Haloboron Carbanionsmentioning

confidence: 99%

α‐Boryl Carbanions: The Influence of Geminal Heteroatoms in C−C Bond Formation

Fernández

2024

The Chemical Record

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The wide applications of alpha‐boryl carbanions in selective coupling with organohalides, imines/carbonyls and conjugated unsaturated substrates has become an interesting tool for organic synthesis. Strategically, the inclusion of heteroatoms, such as Si, S, N, F, Cl, Br and I in the alpha position opens a new venue towards multifunctionalities in molecular design. Here, a conceptual and practical view on powerful carbanions, containing α‐silicoboron, α‐thioboron, α‐haloboron and α‐aminoboron is given, as well as a prespective on their efficient application for selective electrophilic trapping.

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“…[23] However, a photocatalytic approach for the synthesis of cyclopropanes using gemdiborylalkanes as C 1 reagents has not been explored. We present herein the photoinduced borylcyclopropanation of alkenes with a (diborylmethyl)iodide reagent, [24] which can be readily prepared from bis[(pinacolato)boryl]methane in a single step (Scheme 1b), noting that bis[(pinacolato)boryl]methane can be prepared directly by Cu-catalyzed borylation of CH 2 Cl 2 . [25] Our visible-lightinduced strategy provides access to a series of stereodefined cyclopropyl boronic esters in good yields under mild conditions.…”

Section: Introductionmentioning

confidence: 99%

Photocatalyzed Borylcyclopropanation of Alkenes with a (Diborylmethyl)iodide Reagent

Hu,

Tang,

Wang

et al. 2023

Angew Chem Int Ed

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Cyclopropane skeletons play a prominent role in the development of organic synthesis and pharmaceutical chemistry. Herein, we report the design and synthesis of a stable, multifunctional (diborylmethyl)iodide reagent (CHI(Bpin)2) for the photoinduced cyclopropanation of alkenes, providing an array of 1,2‐substituted cyclopropylboronates in good yields. This α‐haloboronic ester can be readily synthesized on a multigram scale from commercially available starting materials. Furthermore, this protocol displays high chemo‐ and diastereoselectivity, excellent functional group tolerance, and allows for late‐stage borylcyclopropanation of complex molecules. Mechanistic studies reveal that the borylcyclopropanation proceeds via a radical addition/polar cyclization pathway mediated by the photocatalyst fac‐Ir(ppy)3 and visible light.

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A Novel Synthesis of Halogenated gem-Diboron Reagents

Cited by 19 publications

References 47 publications

A General Method to Access Sterically Encumbered Geminal Bis(boronates) via Formal Umpolung Transformation of Terminal Diboron Compounds

A General Method to Access Sterically Encumbered Geminal Bis(boronates) via Formal Umpolung Transformation of Terminal Diboron Compounds

α‐Boryl Carbanions: The Influence of Geminal Heteroatoms in C−C Bond Formation

Photocatalyzed Borylcyclopropanation of Alkenes with a (Diborylmethyl)iodide Reagent

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