Coordination Switch Drives Selective C−S Bond Formation by the Non‐Heme Sulfoxide Synthases**

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(50)

Опубликована: Окт. 19, 2022

The non-heme iron ergothioneine synthase (EgtB) is a sulfoxide that catalyzes oxidative C-S bond formation in the synthesis of ergothioneine, which plays roles against stress cells. Despite extensive experimental and computational studies catalytic mechanisms EgtB, root causes for selective remain elusive. Using quantum mechanics/molecular mechanics (QM/MM) calculations, we show herein coordination switch intermediate involved catalysis EgtB. This from S to O atom driven by S/π electrostatic interactions, efficiently promotes observed stereoselective while bypassing cysteine dioxygenation. present mechanism agreement with all available data, including regioselectivity, stereoselectivity KIE results. match underscores critical role switching enzymes.

Язык: Английский

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Asymmetric Büchner reaction and arene cyclopropanation via copper-catalyzed controllable cyclization of diynes

Nature Communications, Год журнала: 2024, Номер 15(1)

Опубликована: Окт. 25, 2024

The asymmetric Büchner reaction and related arene cyclopropanations represent one type of the powerful methods for enantioselective dearomatization. However, examples reactions via a non-diazo approach are quite scarce, cyclopropanation based on alkynes has not been reported. Herein, we disclose an by copper-catalyzed controllable cyclization N-propargyl ynamides vinyl cation intermediates, leading to chiral tricycle-fused cycloheptatrienes benzonorcaradienes in high yields enantioselectivities. Importantly, this protocol represents cations.

Язык: Английский

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Enantioselective Desymmetrizing Hydroalkoxylation of 1,4- and 1,8-Diynes Enabled by Chiral Brønsted Acid Catalysis

ACS Catalysis, Год журнала: 2023, Номер 13(13), С. 8803 - 8812

Опубликована: Июнь 19, 2023

Herein, an organocatalytic enantioselective desymmetrizing hydroalkoxylation of 1,4- and 1,8-diynes is disclosed, which represents a unique chiral Brønsted acid-catalyzed desymmetrization diynes. This protocol provides facile practical access to enantioenriched 1,3-diaminopropanol derivatives γ-butyrolactones with wide substrate scope generally high enantioselectivities. Besides, the backbones these products constitute structural core numerous bioactive molecules, they can serve as valuable precursors for expeditious assembly versatile N- O-heterocycles. Moreover, control experiments theoretical calculations are employed confirm mechanistic rationale elucidate origin enantioinduction.

Язык: Английский

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Ir/Zn-cocatalyzed chemo- and atroposelective [2+2+2] cycloaddition for construction of C─N axially chiral indoles and pyrroles

Science Advances, Год журнала: 2023, Номер 9(51)

Опубликована: Дек. 20, 2023

Here, an Ir/Zn-cocatalyzed atroposelective [2+2+2] cycloaddition of 1,6-diynes and ynamines was developed, forging various functionalized C─N axially chiral indoles pyrroles in generally good to excellent yields (up 99%), chemoselectivities, high enantioselectivities 98% enantiomeric excess) with wide substrate scope. This cocatalyzed strategy not only provided alternative promising reliable way for asymmetric alkyne cyclotrimerization easy handle but also settled the issues previous [Rh(COD)2]BF4-catalyzed system on construction axial chirality such as complex operations, limited scope, low efficiency. In addition, control experiments theoretical calculations disclosed that Zn(OTf)2 markedly reduced barrier migration insertion significantly increase reaction efficiency, which distinctly different from work Lewis acid improving yield through accelerating oxidative addition reductive elimination.

Язык: Английский

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A copper-catalyzed B–H bond insertion reaction of azide–ynamide with borane adductsviaα-imino copper carbenes

Organic Chemistry Frontiers, Год журнала: 2022, Номер 9(10), С. 2773 - 2778

Опубликована: Янв. 1, 2022

A new copper-catalyzed B–H bond insertion into α-imino copper carbenes generated from azide–ynamide cyclization has been developed, leading to a facile and practical synthesis of series α-boryl amidines.

Язык: Английский

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