Zinc Catalyzed Hydroelementation (HE; E = B, C, N, and O) of Carbodiimides: Intermediates Isolation and Mechanistic Insights
作者:Rajata Kumar Sahoo、Arukela Ganesh Patro、Nabin Sarkar、Sharanappa Nembenna
DOI:10.1021/acs.organomet.2c00610
日期:——
The conjugated bis-guanidinate (CBG) supported zinc hydride, [LZnH}2; L = (ArHN)(ArN)-C═N–C═(NAr)(NHAr); Ar = 2,6-Et2-C6H3}] (1) (pre)-catalyzed addition of E–H (E = B, C, N, and O) to carbodiimides is presented. Compound 1 catalyzed the reduction of carbodiimides with pinacolborane (HBpin), terminal alkynes, primary amines, and alcohols, gave a series of N-boryl formamidines, propiolamidines, guanidines
共轭双胍(CBG)负载的氢化锌,[LZnH} 2;L = (ArHN)(ArN)-C=N–C=(NAr)(NHAr); Ar = 2,6-Et 2 -C 6 H 3 }] ( 1 ) (预)催化E-H (E = B、C、N和O)加成至碳二亚胺。化合物1用频那醇硼烷(HBpin)、末端炔烃、伯胺和醇催化碳二亚胺还原,得到一系列高转化率的N-硼基甲脒、丙啶脒、胍和异脲。所有这些反应都表现出良好的官能团耐受性。这些反应通过活性催化剂和脒酸锌中间体(Zn-1 , Zn-1′、和Zn-3)、炔基锌(Zn-2和Zn-2')、苯胺锌(Zn-4)和醇锌(Zn-5)配合物,已通过多核 NMR 和 HRMS 分析进行了表征。此外,化合物Zn-1'、Zn-2'、Zn-4和Zn-5通过单晶 X 射线衍射研究得到证实。基于明确的中间体和化学计量实验,提出了完整的催化循环。