Developments in Photoredox/Nickel Dual-Catalyzed 1,2-Difunctionalizations

Chem, Journal Year: 2020, Volume and Issue: 6(6), P. 1327 - 1339

Published: June 1, 2020

Language: Английский

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Mechanism of Ni-Catalyzed Reductive 1,2-Dicarbofunctionalization of Alkenes

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(44), P. 17937 - 17948

Published: Oct. 7, 2019

Ni-catalyzed cross-electrophile coupling reactions have emerged as appealing methods to construct organic molecules without the use of stoichiometric organometallic reagents. The mechanisms are complex: plausible pathways, such "radical chain" and "sequential reduction" mechanisms, dependent on sequence activation electrophiles. A combination kinetic, spectroscopic, studies reveals that a Ni-catalyzed, reductive 1,2-dicarbofunctionalization alkenes proceeds through pathway. reduction Ni by Zn is turnover-limiting step, consistent with Ni(II) intermediates catalyst resting-state. only sufficient reduce (phen)Ni(II) Ni(I) species. As result, commonly proposed Ni(0) absent under these conditions. (Phen)Ni(I)–Br selectively activates aryl bromides via two-electron oxidation addition, whereas alkyl activated (phen)Ni(I)–Ar single-electron afford radicals. These findings could provide insight into achieving selectivity between different

Language: Английский

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Transition Metal (Ni, Cu, Pd)-Catalyzed Alkene Dicarbofunctionalization Reactions

Accounts of Chemical Research, Journal Year: 2021, Volume and Issue: 54(17), P. 3415 - 3437

Published: Aug. 12, 2021

ConspectusRecently, alkene dicarbofunctionalization, i.e., the powerful organic synthesis method of difunctionalization with two carbon sources, emerged as a formidable reaction immense promise to synthesize complex molecules expeditiously from simple chemicals. This is generally achieved transition metals (TMs) through interception by sources an alkylmetal [β-H–C(sp3)–[M]] species, key intermediate prone undergo rapid β-H elimination. Related prior reports, since Paolo Chiusoli and Catellani's work in 1982 [ Tetrahedron Lett. 1982, 23, 4517], have used bicyclic disubstituted terminal alkenes, wherein elimination avoided geometric restriction or complete lack β-H's. With reasoning that β-H–C(sp3)–[M] intermediates could be rendered amenable use first row late TMs formation coordination-assisted transient metallacycles, these strategies were implemented address problem dicarbofunctionalization reactions.Because catalyze C(sp3)–C(sp3) coupling, Cu Ni anticipated impart sufficient stability intermediates, generated catalytically upon carbometalation, for their subsequent electrophiles/nucleophiles three-component reactions. Additionally, such innate property enable coupling partners entropically driven cyclization/coupling The cyclometalation concept stabilize intractable was hypothesized when reactions performed. idea curtail founded Whitesides's J. Am. Chem. Soc. 1976, 98, 6521] observation metallacycles much slower than acyclic alkylmetals.In this Account, examples demonstrate catalysts alkenylzinc reagents, alkyl halides, aryl halides afford carbo- heterocycles. In addition, forming nickellacycles enabled regioselective performance various alkenyl compounds. situ [M]-H alkenes after induced unprecedented metallacycle contraction process, which six-membered metal-containing rings shrank five-membered cycles, allowing creation new carbon–carbon bonds at allylic (1,3) positions. Applications are discussed.

Language: Английский

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Nickel-catalyzed difunctionalization of allyl moieties using organoboronic acids and halides with divergent regioselectivities

Chemical Science, Journal Year: 2017, Volume and Issue: 9(3), P. 600 - 607

Published: Oct. 26, 2017

We present herein a nickel-catalyzed dicarbofunctionalization of alkenes using readily available organoboronic acids and organic halides in three-component fashion.

Language: Английский

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Ni-Catalyzed Regioselective 1,2-Dicarbofunctionalization of Olefins by Intercepting Heck Intermediates as Imine-Stabilized Transient Metallacycles

Journal of the American Chemical Society, Journal Year: 2017, Volume and Issue: 139(31), P. 10653 - 10656

Published: July 24, 2017

We disclose a strategy for Ni-catalyzed dicarbofunctionalization of olefins in styrenes by intercepting Heck C(sp3)–NiX intermediates with arylzinc reagents. This approach utilizes readily removable imine as coordinating group that plays dual role oxidative addition species derived from aryl halides and triflates to promote carbometalation stabilizing the transient metallacycles suppress β-hydride elimination facilitate transmetalation/reductive steps. method affords diversely substituted 1,1,2-triarylethyl products occur structural motifs various natural products.

Language: Английский

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