Synthesis of 2-(Trifluoromethyl)oxazoles from β-Monosubstituted Enamines via PhI(OCOCF3)2-Mediated Trifluoroacetoxylation and Cyclization
摘要:
Treatment of beta-monosubstituted enamines with phenyliodine bis(trifluoroacetate) (PIFA) was found to give a variety of 4,5-disubstituted 2-(trifluoromethyl)oxazoles. This approach allows the incorporation of the trifluoromethyl moiety in PIFA into the final products, which presumably takes place via the oxidative beta-trifluoroacetoxylation of the enamine substrates followed by subsequent intramolecular cyclization.
Direct Oxidative Coupling of Enamines and Electron-Deficient Amines: TBAI/TBHP-Mediated Synthesis of Substituted Diaminoalkenes under Metal-Free Conditions
作者:Yucheng Yuan、Wenjuan Hou、Daisy Zhang-Negrerie、Kang Zhao、Yunfei Du
DOI:10.1021/ol5026525
日期:2014.10.17
A metal-free cross-coupling of enamines and electron-deficient amines through oxidative C(sp(2))-N bond formation has been realized by using TBAI as catalyst and TBHP as oxidant. This novel strategy allows for an efficient organocatalytic synthesis of the synthetically useful diaminoalkene derivatives and is highlighted by appealing features such as readily available of the starting materials, wide substrate scope and transition-metal-free characteristics.