Enantioselective Copper-Catalyzed Ring-Opening Diboration of Arylidenecyclopropanes to Access Chiral Skipped 1,4- and 1,3-Diboronates

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(8), P. 5366 - 5374

Published: Feb. 14, 2024

Two enantioselective approaches to synthesize chiral skipped diboronate compounds have been developed, relying on copper-catalyzed one-pot asymmetric ring-opening diboration of arylidenecyclopropanes. A wide range arylidenecyclopropanes react smoothly with HBpin in the presence CuOAc and (R)-DTBM-Segphos, affording 1,4-diboronates high enantioselectivity (up 99% ee). Meanwhile, a variety selectively B2pin2 (S,S)-Ph-BPE sequential addition MeOH, providing 1,3-diboronates 98% These enantioenriched 1,3- can undergo various enantiospecific transformations minimal loss their enantiopurity. Mechanistic studies reveal that these two processes start CuH-catalyzed hydroboration form mixture Z/E-homoallyl boronate intermediates, which subsequently second or Cu-Bpin-catalyzed protoboration produce 1,3-diboronates, respectively.

Language: Английский

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Copper-Catalyzed Coupling of Alkyl Vicinal Bis(boronic Esters) to an Array of Electrophiles

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(39), P. 17815 - 17823

Published: Sept. 22, 2022

A neighboring boronate group in the substrate provides a dramatic rate acceleration transmetalation to copper and thereby enables organoboronic esters participate unprecedented site-selective cross-couplings. This cross-coupling operates under practical experimental conditions allows for coupling between vicinal bis(boronic esters) allyl, alkynyl, propargyl electrophiles as well simple proton. Because reactive substrates are esters), described herein an expedient new method construction of boron-containing reaction products from alkenes. Mechanistic experiments suggest that chelated cyclic ate complexes may play role transmetalation.

Language: Английский

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Desymmetrization of Vicinal Bis(boronic) Esters by Enantioselective Suzuki–Miyaura Cross-Coupling Reaction

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(15), P. 8308 - 8313

Published: April 6, 2023

The development of an enantioselective catalytic Suzuki-Miyaura reaction that applies to

Language: Английский

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Nickel-Catalyzed Regio- and Enantioselective Borylative Coupling of Terminal Alkenes with Alkyl Halides Enabled by an Anionic Bisoxazoline Ligand

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(25), P. 13603 - 13614

Published: June 6, 2023

Chiral boronic esters are a class of versatile building blocks. We describe herein an asymmetric nickel-catalyzed borylative coupling terminal alkenes with nonactivated alkyl halides. The success this reaction is ascribed to the application chiral anionic bisoxazoline ligand. This study provides three-component strategy access α- and β-stereogenic from easily accessible starting materials. protocol characterized by mild conditions, wide substrate scope high regio- enantioselectivity. also showcase value method in simplifying synthesis several drug molecules. Mechanistic studies suggest that generation enantioenriched bearing α-stereogenic center results stereoconvergent process, while enantioselectivity-controlling step β-stereocenter switched olefin migratory insertion due coordination ester group.

Language: Английский

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Ir‐Catalyzed Enantioselective Synthesis of gem‐Diborylalkenes Enabled by 1,2‐Boron Shift

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(32)

Published: June 15, 2023

Abstract Asymmetric cross‐couplings based on 1,2‐carbon migration from B‐ate complexes have been developed efficiently to access valuable organoboronates. However, enantioselective reactions triggered by 1,2‐boron shift remained be unaddressed synthetic challenge. Here, Ir‐catalyzed asymmetric allylic alkylation enabled was developed. In this reaction, we disclosed that excellent enantioselectivities were achieved through an interesting dynamic kinetic resolution (DKR) process of carbonates at the elevated temperature. Notably, highly (bis‐boryl)alkenes array diversifications versatile molecules. Extensive experimental and computational studies conducted elucidate reaction mechanism DKR clarify origin enantioselectivities.

Language: Английский

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Enantioselective synthesis of multifunctional alkylboronates via N-heterocyclic carbene–nickel-catalysed carboboration of alkenes

Nature Synthesis, Journal Year: 2024, Volume and Issue: 3(5), P. 633 - 642

Published: March 7, 2024

Language: Английский

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Facile Synthesis of Housanes by an Unexpected Strategy

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 17, 2025

Rigid bicyclic hydrocarbons have emerged as important building blocks in the drug discovery industry. Despite progress this general area, bicyclo[2.1.0]pentanes (housanes) are an understudied class of molecules. Herein we report unconventional synthesis borylated housanes. Our method features a broad scope and high diastereoselectivities versatile intermediates. The route involves strain-release diboration bicyclo[1.1.0]butane intramolecular deborylative alkylation. versatility bridgehead boronic ester was demonstrated several functionalizations. Lastly, mechanism reaction investigated, unusual stereospecific diastereoselective ring expansion uncovered.

Language: Английский

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Stereospecific Transformations of Alkylboronic Esters Enabled by Direct Boron-to-Zinc Transmetalation

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(18), P. 9976 - 9981

Published: April 26, 2023

Chiral secondary organoboronic esters, when activated with t-butyllithium, are shown to undergo efficient stereoretentive transmetalation either zinc acetate or chloride. This reaction provides chiral alkylzinc reagents that configurationally stable under practical experimental conditions. The organozinc compounds were found engage in stereospecific reactions difluorocarbene, catalytic cross-couplings palladium-based catalysts, and trifluoromethylation a copper(III) complex. Mechanistic computational studies shed light on the inner workings of event.

Language: Английский

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Stereospecific Acylative Suzuki–Miyaura Cross-Coupling: General Access to Optically Active α-Aryl Carbonyl Compounds

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(13), P. 7075 - 7083

Published: March 2, 2023

A novel strategy for the stereospecific Pd-catalyzed acylative cross-coupling of enantiomerically enriched alkylboron compounds has been developed. The protocol features an extremely high level enantiospecificity to allow facile access synthetically challenging and valuable chiral ketones carboxylic acid derivatives. use a sterically encumbered electron-rich phosphine ligand proved be crucial success reaction. Furthermore, on basis experimental computational studies, unique mechanism transmetalation, assisted by noncovalent interactions C(sp3)-based organoboron reagent, identified.

Language: Английский

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Ligand Control in Co-Catalyzed Regio- and Enantioselective Hydroboration: Homoallyl Secondary Boronates via Uncommon 4,3-Hydroboration of 1,3-Dienes

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(13), P. 7462 - 7481

Published: March 27, 2023

Enantiopure homoallylic boronate esters are versatile intermediates because the C-B bond in these compounds can be stereospecifically transformed into C-C, C-O, and C-N bonds. Regio- enantioselective synthesis of precursors from 1,3-dienes has few precedents literature. We have identified reaction conditions ligands for nearly enantiopure (er >97:3 to >99:1) via a rarely seen cobalt-catalyzed [4,3]-hydroboration 1,3-dienes. Monosubstituted or 2,4-disubstituted linear dienes undergo highly efficient regio- hydroboration with HBPin catalyzed by [(L*)Co]+[BARF]-, where L* is typically chiral bis-phosphine ligand narrow bite angle. Several such (e.g., i-PrDuPhos, QuinoxP*, Duanphos, BenzP*) that give high enantioselectivities product been identified. In addition, equally challenging problem regioselectivity uniquely solved dibenzooxaphosphole ligand, (R,R)-MeO-BIBOP. A cationic cobalt(I) complex this very (TON >960) catalyst while also providing excellent regioselectivities (rr >98:2) broad range substrates. detailed computational investigation reactions using Co complexes two widely different (BenzP* MeO-BIBOP) employing B3LYP-D3 density functional theory provides key insights mechanism origins selectivities. The results full agreement experiments. For we examined thus far, relative stabilities diastereomeric diene-bound [(L*)Co(η4-diene)]+ lead initial diastereofacial selectivity, which turn retained subsequent steps, exceptional enantioselectivity reactions.

Language: Английский

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