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Palladium‐Catalyzed Cross‐Coupling of Alkenyl Carboxylates
Author(s) -
Becica Joseph,
Heath Oliver R. J.,
Zheng Cameron H. M.,
Leitch David C.
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202006586
Subject(s) - electrophile , chemistry , catalysis , alkene , palladium , carboxylate , combinatorial chemistry , catalytic cycle , oxidative coupling of methane , base (topology) , coupling reaction , coupling (piping) , stereochemistry , organic chemistry , materials science , mathematical analysis , mathematics , metallurgy
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.