title: Cobalt-bisoxazoline-catalyzed asymmetric Kumada cross-coupling of racemic α-bromo esters with aryl Grignard reagents.
abstract: 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 into α-arylcarboxylic acids and primary alcohols without erosion of ee. The new enantioenriched α-arylpropionic esters synthesized herein are potentially useful in the development of nonsteroidal anti-inflammatory drugs. This method was conducted on gram-scale and applied to the synthesis of highly enantioenriched (S)-fenoprofen and (S)-ar-turmerone.
authors.affiliation: Department of Applied Chemistry, China Agricultural University , 2 West Yuanmingyuan Road, Beijing 100193, P.R. China.
authors.forename: Jianyou
authors.initials: J
authors.lastname: Mao
authors.forename: Feipeng
authors.initials: F
authors.lastname: Liu
authors.forename: Min
authors.initials: M
authors.lastname: Wang
authors.forename: Lin
authors.initials: L
authors.lastname: Wu
authors.forename: Bing
authors.initials: B
authors.lastname: Zheng
authors.forename: Shangzhong
authors.initials: S
authors.lastname: Liu
authors.forename: Jiangchun
authors.initials: J
authors.lastname: Zhong
authors.forename: Qinghua
authors.initials: Q
authors.lastname: Bian
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Walsh