A variety of enaminones and enamine carboxylic esters were converted to trifluoroethoxylated 2H-azirines through reactions with PhIO in trifluoroethanol (TFE). The cascade reaction is postulated to proceed via a PhIO-mediated oxidative trifluoroethoxylation and a subsequent azirination of the α-trifluoroethoxylated enamine intermediates.

Formation of Functionalized 2H-Azirines Through PhIO-Mediated Trifluoroethoxylation and Azirination of Enamines. -The facile protocol allows the synthesis of trifluoroethoxylated 2H-azirines via cascade reaction of enaminones or enamine carboxylic esters with trifluoroethanol. The products can undergo FeCl 2 mediated intramolecular ring expansion to produce isoxazoles [cf. synthesis of (IV)]. -(SUN, X.; LYU, Y.; ZHANG-NEGRERIE, D.; DU*, Y.; ZHAO, K.; Org. Lett. 15 (2013) 24, 6222-6225, http://dx.doi.org/10.1021/ol4030716 ; Collab. Innovation Cent. Chem. Sci. Eng., Tianjin 300072, Peop. Rep. China; Eng.) -Mais 21-111