Palladium-Catalyzed Cross-Coupling of Alkenyl Carboxylates.

Autor: Becica J; Department of Chemistry, University of Victoria, 3800 Finnerty Rd., Victoria, BC, V8P 5C2, Canada., Heath ORJ; Department of Chemistry, University of Victoria, 3800 Finnerty Rd., Victoria, BC, V8P 5C2, Canada., Zheng CHM; Department of Chemistry, University of Victoria, 3800 Finnerty Rd., Victoria, BC, V8P 5C2, Canada., Leitch DC; Department of Chemistry, University of Victoria, 3800 Finnerty Rd., Victoria, BC, V8P 5C2, Canada.
Jazyk: angličtina
Zdroj: Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2020 Sep 21; Vol. 59 (39), pp. 17277-17281. Date of Electronic Publication: 2020 Jul 28.
DOI: 10.1002/anie.202006586
Abstrakt: Carboxylate esters have many desirable features as electrophiles for catalytic cross-coupling: they are easy to access, robust during multistep synthesis, and mass-efficient in coupling reactions. Alkenyl carboxylates, a class of readily prepared non-aromatic electrophiles, remain difficult to functionalize through cross-coupling. We demonstrate that Pd catalysis is effective for coupling electron-deficient alkenyl carboxylates with arylboronic acids in the absence of base or oxidants. Furthermore, these reactions can proceed by two distinct mechanisms for C-O bond activation. A Pd 0/II catalytic cycle is viable when using a Pd 0 precatalyst, with turnover-limiting C-O oxidative addition; however, an alternative pathway that involves alkene carbopalladation and β-carboxyl elimination is proposed for Pd II precatalysts. This work provides a clear path toward engaging myriad oxygen-based electrophiles in Pd-catalyzed cross-coupling.
(© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)
Databáze: MEDLINE
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