The first cobalt-catalyzed asymmetric Kumada cross-coupling with high enantioselectivity has been developed. The reaction affords a unique strategy for the enantioselective arylation of α-bromo esters catalyzed by a cobalt-bisoxazoline complex. A variety of chiral α-arylalkanoic esters were prepared in excellent enantioselectivity and yield (up to 97% ee and 96% yield). The arylated products were transformed
enantioselective Negishi cross‐coupling reaction, and the first arylation of α‐halo esters with arylzinc halides, are disclosed. Employing a cobalt‐bisoxazoline catalyst, various α‐arylalkanoic esters were synthesized in excellent enantioselectivities and yields (up to 97 % ee and 98 % yield). A diverse range of functional groups, including ether, halide, thioether, silyl, amine, ester, acetal, amide, olefin
Nickel/Photoredox‐Catalyzed Asymmetric Reductive Cross‐Coupling of Racemic α‐Chloro Esters with Aryl Iodides
作者:Haixing Guan、Qianwen Zhang、Patrick J. Walsh、Jianyou Mao
DOI:10.1002/anie.201914175
日期:2020.3.23
A unique nickel/organic photoredox co-catalyzed asymmetricreductive cross-coupling between α-chloro esters and aryl iodides is developed. This cross-electrophile coupling reaction employs an organic reductant (Hantzschester), whereas most reductive cross-coupling reactions use stoichiometric metals. A diverse array of valuable α-aryl esters is formed under these conditions with high enantioselectivities
The first iron-catalyzed enantioselective cross-coupling reaction between an organometallic compound and an organic electrophile is reported. Synthetically versatile racemic α-chloro- and α-bromoalkanoates were coupled with aryl Grignard reagents in the presence of catalytic amounts of an iron salt and a chiral bisphosphine ligand, giving the products in high yields with acceptable and synthetically
facile access to various opticallyactive α-arylpropionic acids including several nonsteroidal anti-inflammatory drugs (NSAIDs) of commercial importance. (R,R)-QuinoxP* is specifically able to induce chirality when compared to analogous P-chiral ligands that give racemic products, highlighting the critical importance of transmetalation in the present asymmetric cross-coupling system.