Regioselective Cycloaddition of Trifluorodiazoethane with Electron-Deficient Allenic Esters and Ketones: Access to CF<sub>3</sub>-Substituted Pyrazolines and Pyrazoles
作者:Fa-Guang Zhang、Yi Wei、Yu-Ping Yi、Jing Nie、Jun-An Ma
DOI:10.1021/ol501249h
日期:2014.6.6
A highly regioselective cycloaddition procedure of electron-deficient allenes with trifluorodiazoethane (CF3CHN2) is described. In absence of bases, the reaction proceeded smoothly to give 5-(trifluoromethyl)pyrazolines, whereas the utility of Et3N led to the formation of 3-(trifluoromethyl)pyrazoles.