用于Biginelli反应的二茂钛的氮供体配体活化——亚胺机理

Zheng Shaohua, Jian Yajun, Xu Shan, Wu Ya, Sun Huaming, Zhang Guofang, Zhang Weiqiang, Gao Ziwei

Key Laboratory of Applied Surface and Colloid Chemistry, MOE, School of Chemistry and Chemical Engineering, Shaanxi Normal University Xi'an 710062 China

College of Chemistry and Chemical Engineering, Xi'an Shiyou University Xi'an 710065 P. R. China.

RSC Adv. 2018 Feb 27;8(16):8657-8661. doi: 10.1039/c8ra01208c. eCollection 2018 Feb 23.

The remarkable activation of stable titanocene dichloride (CpTiCl) was achieved using N-donor ligand urea in an alcoholic solvent, leading to the formation of a Ti(iv) species [(MeO)Ti(NHCONH)], the existence of which was verified by ESI-MS, ESI-MS/MS, and NMR. Catalyzed by the newly formed Ti(iv) species, a myriad of 3,4-dihydropyrimidin-2-(1)-ones were produced a three-component Biginelli reaction. Further mechanistic investigation indicated that the Biginelli reaction had taken place the imine route.

在醇类溶剂中使用氮供体配体尿素实现了稳定的二氯二茂钛（CpTiCl）的显著活化，导致形成了一种Ti(IV) 物种[(MeO)Ti(NHCONH)]，其存在通过电喷雾电离质谱（ESI-MS）、串联电喷雾电离质谱（ESI-MS/MS）和核磁共振（NMR）得到证实。在新形成的Ti(IV) 物种催化下，通过三组分Biginelli反应生成了大量的3,4-二氢嘧啶-2-(1H)-酮。进一步的机理研究表明，Biginelli反应是通过亚胺途径发生的。