Hemiacetal and hemiaminal formation at fluoroacyl moiety

Hemiacetals and hemiaminals were produced not only at a trifluoroacetyl (CF3CO) moiety but also at difluoroacetyl (CHF2CO) and pentafluoroalkanoyl (C2F5CO) moieties. As larger was the electron-withdrawing nature and less bulky was the fluoroalkyl (Rf) group and smaller was the size of an alcohol, the ratio of hemiacetal form increased. Not only a CF3CO moiety but also monofluoroacetyl (CH2FCO), CHF2CO, and C2F5CO moieties produced the hemiaminals. As larger was the electron-withdrawing nature of Rf group and smaller was an amine, the ratio of hemiaminal form increased.