Carbene B−H Insertion Reactions for C−B Bond Formation

Zhao, Ximei; Wang, Guanghui; Hashmi, A. Stephen K.

doi:10.1002/cctc.202100914

Cited by 23 publications

(8 citation statements)

References 58 publications

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“…Organic boron compounds are widely used in organic synthesis, medicine, and materials science . The synthesis of chiral organoboron compounds has attracted considerable attention, and a number of enantioselective methods have been established . However, although chiral propargylic boron compounds (in which the boron atom is directly connected to the propargylic carbon chiral center) contain easily transformable alkynyl and boron moieties and thus have high potential utility, the synthesis of these compounds remains a significant challenge .…”

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confidence: 99%

Catalytic Asymmetric Synthesis of Chiral Propargylic Boron Compounds through B–H Bond Insertion Reactions

et al. 2022

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Chiral propargylic boron compounds have a diverse array of potential applications. Although numbers of highly enantioselective methodologies for the synthesis of other organoboron compounds are well established, highly enantioselective synthesis of chiral propargylic boron compounds remains unknown. Herein, we report a catalytic method for the construction of chiral propargylic boron compounds by means of highly enantioselective dirhodium-catalyzed B−H bond insertion reactions using aryl propargylic sulfonylhydrazones as carbene precursors. This method enables the straightforward synthesis of a wide range of stable chiral propargylic boron compounds in yields up to 99% with enantioselectivities up to 97% ee. The operationally simple method features a broad substrate scope, good functional group tolerance, and mild reaction conditions. The boron compounds prepared in this study are inaccessible by other known methods and exhibit high potential utility because they could be efficiently transformed into allenyl borates, triazole borane compounds, and homopropargylic and propargylic alcohols with good enantiomeric fidelity. Our work expands the library of catalytic B−H bond insertion reactions, increases the variety of chiral organoboron compounds that can be synthesized, and provides preliminary information about possible transformations of chiral propargylic boron compounds, thus laying the foundation for wide application of these compounds.

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confidence: 99%

Catalytic Asymmetric Synthesis of Chiral Propargylic Boron Compounds through B–H Bond Insertion Reactions

et al. 2022

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“…We began by carrying out a series of control experiments. A deuterium labeling experiment indicated that a B─H insertion (20)(21)(22) process was involved in the transformation (fig. S1A).…”

Section: Mechanistic Studiesmentioning

confidence: 99%

Wittig/B─H insertion reaction: A unique access to trisubstituted Z -alkenes

Guo,

Lu,

Huang

et al. 2023

Sci. Adv.

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The Wittig reaction, which is one of the most effective methods for synthesizing alkenes from carbonyl compounds, generally gives thermodynamically stable E -alkenes, and synthesis of trisubstituted Z -alkenes from ketones presents notable challenges. Here, we report what we refer to as Wittig/B─H insertion reactions, which innovatively combine a Wittig reaction with carbene insertion into a B─H bond and constitute a promising method for the synthesis of thermodynamically unstable trisubstituted Z -boryl alkenes. Combined with the easy transformations of boryl group, this methodology provides efficient access to a variety of previously unavailable trisubstituted Z -alkenes and thus provides a platform for discovery of pharmaceuticals. The unique Z- selectivity of the reaction is determined by the maximum overlap of the orbitals between the B─H bond of the borane adduct and the alkylidene carbene intermediate in the transition state.

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“…As for organoboron compounds, several protocols, including the hydroborations of olefins and C-H bond borylations, offer straightforward access to establish B-C bond [ 27 , 28 , 29 ]. In addition to the above-mentioned methods, the insertion of carbene species into the X-H (X = Si, B) bond stands for another highly efficient route to construct Si-C and B-C bonds [ 30 , 31 ]. The past few decades have witnessed the tremendous development of X-H insertions.…”

Section: Introductionmentioning

confidence: 99%

X-H Bond Insertion Promoted by Heterogeneous Dirhodium Metal–Organic Cage with Alkynes as Safe Carbene Precursors

Chen

Zhao

et al. 2023

Molecules

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A facile and efficient methodology for the generation of the C-X (X = Si, B) bond through a carbene insertion process was demonstrated using a dirhodium metal–organic cage, MOC-Rh-1, as a heterogeneous catalyst. A series of functionalized alkynes were utilized as safe carbene precursors to furnish Si-H and B-H insertion products in moderate to excellent yields. These reactions featured a high atom-economy, a broad substrate scope, and mild reaction conditions. Moreover, the as-prepared MOC-Rh-1 catalyst was recovered easily from the reaction system by simple centrifugation and reused for ten runs without a significant loss in activity, which made good use of the valuable precious metal rhodium.

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Carbene B−H Insertion Reactions for C−B Bond Formation

Cited by 23 publications

References 58 publications

Catalytic Asymmetric Synthesis of Chiral Propargylic Boron Compounds through B–H Bond Insertion Reactions

Catalytic Asymmetric Synthesis of Chiral Propargylic Boron Compounds through B–H Bond Insertion Reactions

Wittig/B─H insertion reaction: A unique access to trisubstituted Z -alkenes

X-H Bond Insertion Promoted by Heterogeneous Dirhodium Metal–Organic Cage with Alkynes as Safe Carbene Precursors

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