Phenylselenenylation of azaenolates, formed by LDA treatment of dimethylhydrazones 1 (R2= H) and derived from linear aliphatic aldehydes, has led to α-phenylselanyl hydrazones 2. α-Phenylselanyl nitriles 3 were, however, isolated when an excess of base and of PhSeX (X= Cl, Br) were used. Hydrazones 1 bearing an α-alkyl substituent (R2≠ H) gave also nitriles 3. SAMP-hydrazones 4 showed the same reactivity and the corresponding nitriles ...