Asymmetric Photocatalytic C(sp³)–H Bond Addition to α-Substituted Acrylates

Organic Letters, Journal Year: 2021, Volume and Issue: 23(8), P. 3157 - 3161

Published: March 29, 2021

Asymmetric functionalization of inert C(sp3)-H bonds is a straightforward approach to realize versatile bond-forming events, allowing the precise assembly molecular complexity with minimal functional manipulations. Here, we describe an asymmetric photocatalytic bond addition α-substituted acrylates by using tetrabutylammonium decatungstate (TBADT) as hydrogen atom transfer (HAT) photocatalyst and chiral phosphoric acid proton-transfer shuttle. This protocol supposed occur via radical/ionic relay process, including TBADT-mediated HAT cleave bond, 1,4-radical addition, back abstraction, enantioselective protonation. A variety C-H patterns are well tolerated enable rapid synthesis enantioenriched α-stereogenic esters from simple raw materials.

Language: Английский

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Copper-Catalyzed Cross-Coupling of Benzylic C–H Bonds and Azoles with Controlled N-Site Selectivity

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(36), P. 14438 - 14444

Published: Aug. 31, 2021

Azoles are important motifs in medicinal chemistry, and elaboration of their structures via direct N-H/C-H coupling could have broad utility drug discovery. The ambident reactivity many azoles, however, presents significant selectivity challenges. Here, we report a copper-catalyzed method that achieves site-selective cross-coupling pyrazoles other N-H heterocycles with substrates bearing (hetero)benzylic C-H bonds. Excellent

Language: Английский

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Metalloradical Activation of In Situ-Generated α-Alkynyldiazomethanes for Asymmetric Radical Cyclopropanation of Alkenes

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(5), P. 2368 - 2378

Published: Jan. 31, 2022

α-Alkynyldiazomethanes, generated in situ from the corresponding sulfonyl hydrazones presence of a base, can serve as effective metalloradicophiles Co(II)-based metalloradical catalysis (MRC) for asymmetric cyclopropanation alkenes. With D2-symmetric chiral amidoporphyrin 2,6-DiMeO-QingPhyrin optimal supporting ligand, system efficiently activate different α-alkynyldiazomethanes at room temperature highly broad range This catalytic radical process provides general synthetic tool stereoselective construction alkynyl cyclopropanes high yields with both diastereoselectivity and enantioselectivity. Combined computational experimental studies offer several lines evidence support underlying stepwise mechanism Co(II)-catalyzed olefin involving unique α-metalloradical intermediate that is associated two resonance forms α-Co(III)-propargyl γ-Co(III)-allenyl radical. The resulting enantioenriched cyclopropanes, showcased stereospecific transformations, may valuable building blocks organic synthesis.

Language: Английский

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Strategies That Utilize Ion Pairing Interactions to Exert Selectivity Control in the Functionalization of C–H Bonds

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(40), P. 18195 - 18211

Published: Sept. 30, 2022

Electrostatic attraction between two groups of opposite charge, typically known as ion-pairing, offers unique opportunities for the design systems to enable selectivity control in chemical reactions. Catalysis using noncovalent interactions is an established and vibrant research area, but it noticeable that hydrogen bonding are still main interaction choice system design. Opposite charges experience powerful force Coulombic have ability exert fundamental influence on outcome reactions involve charged reagents, intermediates or catalysts. In this Perspective, we will examine how ion-pairing been used C-H bond functionalization processes. This broad class provides interesting thought-provoking lens through which application strategies because one encompasses great mechanistic diversity, poses significant challenges, perhaps most importantly immense interest synthetic chemists both industry academia. We survey proceed via radical ionic mechanisms alongside those transition metal catalysis deal with site-selectivity enantioselectivity. anticipate emerging area develops, become ever-more important strategy control.

Language: Английский

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A general copper-catalysed enantioconvergent radical Michaelis–Becker-type C(sp3)–P cross-coupling

Nature Synthesis, Journal Year: 2023, Volume and Issue: 2(5), P. 430 - 438

Published: Feb. 23, 2023

Language: Английский

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