Hidden Boron Catalysis: Nucleophile-Promoted Decomposition of HBpin

Organic Letters, Journal Year: 2020, Volume and Issue: 22(11), P. 4107 - 4112

Published: May 7, 2020

Simple nucleophiles with structural similarities to known hydroboration catalysts can readily mediate the formation of BH3 and borohydride species from pinacolborane (HBpin). Alkyne alkene reactions were successfully mediated by through generation, BH3-catalyzed found dominate catalysis. NMR spectroscopy kinetic analyses showed that NaOtBu, Na[N(SiMe3)2], nBu2Mg, nBuLi only promoted not "true" catalysts.

Language: Английский

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Direct Synthesis of Multi(boronate) Esters from Alkenes and Alkynes via Hydroboration and Boration Reactions

ACS Catalysis, Journal Year: 2020, Volume and Issue: 11(1), P. 1 - 18

Published: Dec. 10, 2020

Multi(boronate) esters have been attracting increasing attention as versatile building blocks for the succinct and precise synthesis of complex molecules. However, there are a limited number efficient synthetic procedures available. In this respect, direct multiboration alkenes alkynes is undoubtedly an ideal route their synthesis. During past 30 years, catalytic systems based on transition-metals, organophosphines, bases, even catalyst-free systems, with heat or light irradiation straightforward preparation from developed. different numbers (up to 4) positional relationships adjacent boron moieties were obtained, which summarized discussed herein.

Language: Английский

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Advances in transition metal-free deborylative transformations of gem-diborylalkanes

Chemical Communications, Journal Year: 2021, Volume and Issue: 57(36), P. 4346 - 4353

Published: Jan. 1, 2021

This article highlights recent advances on the base-promoted deborylative carbon–carbon and carbon–boron bond-forming reactions using gem-diborylalkanes as sources of α-borylcabanions.

Language: Английский

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α-Boryl Organometallic Reagents in Catalytic Asymmetric Synthesis

ACS Catalysis, Journal Year: 2021, Volume and Issue: 11(16), P. 10660 - 10680

Published: Aug. 12, 2021

Recent years have witnessed an increase in the popularity of α-boryl organometallic reagents as versatile nucleophiles asymmetric synthesis. These compounds been adopted chemo- and stereoselective coupling reactions with a number different electrophiles. The resulting enantioenriched boronic esters can be applied stereospecific carbon-carbon or carbon-heteroatom bond construction reactions, enabling two-step strategy for complex structures high efficiency functional group compatibility. Due to these reasons, tremendous effort has devoted preparation enantiomerically enriched development related racemic prochiral materials. In this review, we describe enantio- diastereoselective that involve starting materials products showcase their synthetic utility.

Language: Английский

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Diborodichloromethane as Versatile Reagent for Chemodivergent Synthesis of gem‐Diborylalkanes

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 63(3)

Published: Dec. 8, 2023

Abstract The development of boron reagents is crucial for synthetic chemistry. Herein, we present a scalable and practical synthesis diborodichloromethane (DBDCM) through the reaction trichloromethyllithium with bis(pinacolato)diboron (B 2 pin ). resulting DBDCM reagent serves as basic unit construction various structurally diverse gem ‐diborylalkanes controllable C−Cl functionalizations. Moreover, have developed consecutive tetra‐functionalizations tertiary quaternary carbon containing molecules. use isotopically enriched 13 C‐chloroform 10 B enables C‐DBDCM B‐DBDCM reagents, which are beneficial convenient carbon‐13 boron‐10

Language: Английский

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Ir-Catalyzed Regioselective Dihydroboration of Thioalkynes toward Gem-Diboryl Thioethers

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(4), P. 2305 - 2314

Published: Jan. 19, 2023

While 1,1-diboryl (gem-diboryl) compounds are valuable synthetic building blocks, currently, related studies have mainly focused on those alkanes without a hetero functional group in the α-position. gem-Diboryl with an α-hetero substituent, though highly versatile, been limitedly accessible and thus rarely utilized. Herein, we developed first α-dihydroboration of heteroalkynes leading to efficient construction gem-diboryl, hetero-, tetra-substituted carbon centers. This straightforward, practical, mild, atom-economic reaction is attractive complement conventional multistep strategy relying deprotonation gem-diborylmethane by strong base. Specifically, [Ir(cod)(OMe)]2 was found be uniquely effective for this process thioalkynes, excellent α-regioselectivity when delivering two boryl groups, which remarkable view many competitive paths including monohydroboration, 1,2-dihydroboration, dehydrodiboration, triboration, tetraboration, etc. Control experiments combined DFT calculations suggested that involves sequential hydroboration events. The second requires higher energy barrier due severe steric repulsion generating congested α-sulfenyl gem-diboryl center, structural motif almost unknown before.

Language: Английский

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A Novel Synthesis of Halogenated gem-Diboron Reagents

Chinese Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 43(2), P. 777 - 777

Published: Jan. 1, 2023

A novel synthesis of halogenated gem-diboronates (X-CR(Bpin)2) was developed.The reagents are stable and easy to prepare in a large scale.Tetra-substituted can be prepared high yields when using alkylsubstituted gem-dihalides, providing new strategy for the gem-diboron compounds.

Language: Английский

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Triethoxysilane-Catalyzed Single and Sequential Regioselective Hydroboration of Terminal Alkynes: Sustainable Access to E-Alkenylboronate and Alkyl Gem-Diboronate Esters by Non-Covalent Interactions

ACS Catalysis, Journal Year: 2025, Volume and Issue: unknown, P. 976 - 981

Published: Jan. 1, 2025

Triethoxysilane was found to be an efficient catalyst for the synthesis of E-alkenyl- and alkyl-di-boronate esters by single sequential hydroboration terminal alkynes, respectively, with pinacolborane. Mechanistic studies support that formation diboronate proceeds a double pathway steric electronic profile at Si being key enabling second step. Weak non-covalent interactions involving C≡C or C═C bonds in alkynes alkenylboronate have been identified as responsible substrate activation toward addition HBPin.

Language: Английский

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Borane-Catalyzed C(sp³)–F Bond Arylation and Esterification Enabled by Transborylation

ACS Catalysis, Journal Year: 2021, Volume and Issue: 11(6), P. 3190 - 3197

Published: Feb. 25, 2021

The activation and functionalization of carbon–fluorine bonds represent a significant synthetic challenge, given the high thermodynamic barrier to C–F bond cleavage. Stoichiometric hydridoborane-mediated has recently emerged, but is yet be rendered catalytic. Herein, borane-catalyzed coupling alkyl fluorides with arenes (carbon–carbon formation) carboxylic acids (carbon–oxygen been developed using transborylation reactions achieve catalytic turnover. Successful C–C C–O across variety structurally electronically differentiated was achieved 9-borabicyclo[3.3.1]nonane (H-B-9-BBN) as catalyst pinacolborane (HBpin), broad functional group tolerance. Experimental computational studies suggest mechanistic dichotomy for carbon–carbon carbon–oxygen reactions. B–F (B–F/B–H metathesis) between F-B-9-BBN HBpin enabled turnover formation, whereas direct exchange fluoride acyloxyboronic ester (C–F/B–O proposed coupling, where H-B-9-BBN catalyzed dehydrocoupling acid HBpin.

Language: Английский

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Alkyne synthesis through coupling of gem-diborylalkanes with carboxylic acid esters

Nature Synthesis, Journal Year: 2023, Volume and Issue: 2(5), P. 413 - 422

Published: Feb. 23, 2023

Language: Английский

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