Abstract: Various perhaloaldehyde N-acyl hemiaminals 1 are readily prepared in high yields by condensation of amides 7 with easily available perhaloaldehyde O-ethyl hemiacetals 8 or hydrates 9 in the presence of 5 Å molecular sieves. Key words: addition reactions, hemiaminals, fluorine, aldehydes, halides, pseudopeptidic transition state analogs, molecular sieves, perhalogenated aldehyde adducts, side chain peptides
