Gold-Catalyzed [4+2]- and [3+3]-Annulations of Ynamides with 1-Yn-3-ols to Access Six-Membered Carbocycles and Oxacycles <i>via</i>
Three Distinct Cyclizations
作者:Sovan Sundar Giri、Rai-Shung Liu
DOI:10.1002/adsc.201700784
日期:2017.10.4
and 1‐yn‐3‐ols are described; the resulting carbo‐ and heterocycles were produced efficiently in one‐pot operations using a gold catalyst. The chemoselectivities of these annulations are controlled by variations of the substituents of the ynamides and the 1‐yn‐3‐ols. This reaction sequence involves initial alkoxylations of ynamides, followed by Claisen rearrangement of propargylic enolethers, and ends
Synthesis of α-Fluorinated Imides via Direct Fluorohydroxylation of Ynamides
作者:Ji-Lin Li、E. Lin、Xiang-Lei Han、Qingjiang Li、Honggen Wang
DOI:10.1021/acs.orglett.9b01428
日期:2019.6.7
A practical synthesis of α-fluorinated imides via the catalyst-free fluorohydroxylation of ynamides is developed. The reaction employs commercially available Selectfluor (F-TEDA-BF4) and H2O as the fluorine and hydroxyl sources, respectively. A broad range of aryl- or alkyl-substituted ynamides were well applicable to the reaction with good functional group tolerance under simple and mild reaction
Benzofurazan <i>N</i>-Oxides as Mild Reagents for the Generation of α-Imino Gold Carbenes: Synthesis of Functionalized 7-Nitroindoles
作者:Wei Xu、Yulong Chen、Ali Wang、Yuanhong Liu
DOI:10.1021/acs.orglett.9b02893
日期:2019.9.20
An efficient gold-catalyzed [3 + 2] annulation of benzofurazan N-oxides with ynamides has been developed, which provides a concise and regioselective access to highly functionalized 7-nitroindoles. Although N-oxides are often considered as oxygentransfer reagents in gold catalysis, benzofurazan N-oxide was found to act as a facile precursor for an α-imino gold carbene intermediate. Benzofurazan can