of racemic β-halo-α-keto esters through carbonyl-enereaction were realized using a chiral N,N′-dioxide-nickel(II) complex, giving the corresponding β-halo-α-hydroxy esters containing two vicinal chiral tri- and tetrasubstituted carbon centers in good yields and dr with excellent ee values without the use of extra bases. Meanwhile, a proposed reactionmechanism was presented according to the configuration
Facile, Selective, and Regiocontrolled Synthesis of Oxazolines and Oxazoles Mediated by ZnI<sub>2</sub> and FeCl<sub>3</sub>
作者:Gopal Chandru Senadi、Wan-Ping Hu、Jia-Shing Hsiao、Jaya Kishore Vandavasi、Chung-Yu Chen、Jeh-Jeng Wang
DOI:10.1021/ol301980g
日期:2012.9.7
An expedient method for a direct approach to the selective and regiocontrolled synthesis of 2-oxazolines and 2-oxazoles mediated by ZnI2 and FeCl3 is described. A Lewis acid promoted cyclization of acetylenic amide with various functionalities was well tolerated to give 2-oxazolines and 2-oxazoles in good to excellent yields under mild reaction conditions.