Metal free regio - and stereoselective semireduction of CF 3 -substituted N -allenamides.

We developed a chemoselective metal-free access for the 1,2- and 2,3-semireduction of CF 3 - N -allenamides. The enamide functionality of CF 3 -substituted N -allenamides could be efficiently reduced by Et 3 SiH/BF 3 ·OEt 2 in total regioselectivity and good stereoselectivity, whereas DBU promoted the isomerization of the resulting allyl amide leading exclusively to the E -configurated enamide.