在此,通过切换反应条件,使用易于获得的烯丙醇,提出了铑(III)催化的β-C(sp 2 )–H烯基化和烯酰胺烷基化。这种可调谐的转化已应用于多种底物,并且通常具有优异的区域选择性和立体选择性以及良好的官能团耐受性。该催化系统提供了一种有效的方法来合成带有N- (2 Z ,4 E )-丁二烯和( Z )-β-C(sp 2 )–H烷基化烯酰胺的各种官能化烯酰胺。此外,机理实验表明,Rh(III) 催化的 C-H 活化与关键步骤无关。
Direct Enamido C(sp<sup>2</sup>)−H Diphosphorylation Enabled by a PCET‐Triggered Double Radical Relay: Access to<i>gem</i>‐Bisphosphonates
作者:Hao‐Qiang Cao、Hao‐Nan Liu、Zhe‐Yuan Liu、Bao‐Kun Qiao、Fa‐Guang Zhang、Jun‐An Ma
DOI:10.1002/chem.202000517
日期:2020.4.24
electron-transfer (PCET)-triggered enamidoC(sp2 )-Hdiphosphorylation. This reaction represents a rare example of realizing the challenging double C-P bond formation at a single carbon atom, thus providing facile access to a broad variety of structurally diverse bisphosphonates from simple enamides under silver-mediated conditions. Initial mechanistic studies demonstrated that the diphosphorylation involves
Metallacrown Ether Catalysts Containing Phosphine-Phosphite Polyether Ligands for Rh-Catalyzed Asymmetric Hydrogenation - Enhancements in Activity and Enantioselectivity
作者:Feng-Tao Song、Guang-Hui Ouyang、Yong Li、Yan-Mei He、Qing-Hua Fan
DOI:10.1002/ejoc.201402735
日期:2014.10
of tunable metallacrown ether rhodium catalysts based on α,ω-(phosphine–phosphite) polyether ligands were prepared either by a template-induced method or by a nontemplate procedure. For the asymmetrichydrogenation of α-arylenamides with the addition of K+ cations, the ortho-diphenylphosphine-substituted metallacrown ether catalyst showed high enantioselectivities (up to 99 % ee), which are comparable
Tetrabutylammonium iodide-catalyzed oxidative coupling of enamides with sulfonylhydrazides: synthesis of β-keto-sulfones
作者:Yucai Tang、Ye Zhang、Kaifeng Wang、Xiaoqing Li、Xiangsheng Xu、Xiaohua Du
DOI:10.1039/c5ob00742a
日期:——
A facile syntheticroutetowards pharmaceutically interesting β-keto-sulfone derivatives by tetrabutylammonium iodide (TBAI)/tert-butyl hydroperoxide (TBHP) mediated oxidative coupling of readily prepared enamides with economical sulfonylhydrazides is described. The corresponding β-keto-sulfone compounds were obtained in moderate to good yields. The present method is metal-free and base-free and shows
Hydrogen peroxide and anhydride mediated transformation of enamides to afford substituted α-acyloxy ketones is described. This transition-metal-free cascade reaction has a broad substrate scope and high efficiency. The acyl intramolecular migration procedure successfully achieved this acyloxylation process under mild conditions and increased the atom efficiency.
Facile Synthesis of Trisubstituted Carbazoles by Acid‐Catalyzed Ring‐Opening Annulation of 2‐Amidodihydrofurans with Indoles
作者:Jingjing Zhao、Pan Li、Chungu Xia、Fuwei Li
DOI:10.1002/chem.201503260
日期:2015.11.9
A mild and convenient synthesis of carbazoles by TfOTMS (trimethylsilyl trifluoromethanesulfonate)‐catalyzedring‐openingannulation of 2‐amidodihydrofurans is presented with a high degree of chemoselectivity and regioselectivity. This procedure was also scaled up to a gram‐scale synthesis. The reaction could involve an iminonium intermediate through a series of CO, CN bond cleavages, CC bond formations