Oxone-promoted hydration of electron-deficient allenic esters and ketones into 1,3-dicarbonyl compounds
摘要:
A novel and mild protocol for the hydration of electron-deficient allenic esters and ketones into various 1,3-dicarbonyl compounds is described. The hydration of allenes promoted by oxone in DMF afforded the corresponding products in moderate to good yields. This work features the employment of only a catalytic amount of inexpensive and nontoxic solid reagent oxone (2KHSO(5)center dot KHSO4 center dot K2SO4), avoiding the utility of toxic metals or traditional Bronsted acids, in a green version of viewpoint. A possible reaction mechanism for this transformation is also primarily proposed. (C) 2015 Elsevier Ltd. All rights reserved.
Et3N-catalyzed direct cycloaddition reaction of allenoates with acceptor diazo compounds
作者:Yu-Ting Tian、Fa-Guang Zhang、Jun-An Ma
DOI:10.1016/j.tet.2021.131922
日期:2021.2
A Et3N-catalyzed [3 + 2] cycloadditionreaction of allenoates with acceptor diazo compounds that include diazoesters, diazoketones, and diazoamides, has been developed. This transformation allows direct and regioselective synthetic route to a variety of pyrazoles from allenoates. 3-Alkynoates also participate in the cycloadditionreaction by isomerizing to the corresponding allenoates in situ.
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.