不对称CH键功能化反应是旋光分子合成中最有效,最直接的方法之一。在这里,我们公开了二茂铁与诸如恶唑和噻唑的唑的不对称CH / CH交叉偶联反应。钯(II)/单保护氨基酸(MPAA)催化体系,对恶唑和噻唑表现出出色的反应性和区域选择性。该方法为构建平面手性二茂铁提供了强有力的策略。机理研究表明,唑类化合物的CH键断裂很可能是通过S E Ar过程进行的,并且可能不是营业额限制步骤。
A Novel and Efficient One Pot Synthesis of 2,4-Disubstituted Thiazoles and Oxazoles Using Phenyltrimethylammoniumtribromide in Ionic Liquid
作者:Manoj Kumar Muthyala、Anil Kumar
DOI:10.1002/jhet.904
日期:2012.7
A novel and efficient one‐pot procedure has been described for synthesis of 2,4‐disubstituted thiazoles and oxazoles from substituted ketones using phenyltrimethylammoniumtribromide as in situ brominating agent followed by reaction with thioamide/thiourea and amides/ureas, respectively in [bmim][BF4] ionicliquid. The advantages of the procedure include avoiding the handling of lacrymetric compounds
cyclization of N-acetyl enamines and intermolecular cyclocondensation of enamines and nitriles was investigated. The reaction was performed under mild conditions and gave oxazoles and imidazoles, respectively, in moderate to excellent yields. This transformation exhibits good reactivity, selectivity and functional group tolerance. The selectivity of the intra- or intermolecular reaction is dependent on the
The asymmetric C–Hbond functionalization reaction is one of the most efficient and straightforward methods for the synthesis of optically active molecules. Herein, our work discovered a Pd-catalyzed asymmetric oxidativeC–H/C–H cross-coupling reaction of ferrocenes with azoles such as oxazoles and thiazoles. Mono-N-protected amino acid as chiral ligands with palladium(II) has been demonstrated as