Synthesis of α-phenylselanyl and α-phenylsulfanyl nitriles from aldehyde N,N-dialkylhydrazones

Phenylselenenylation of azaenolates, formed by LDA treatment of dimethylhydrazones (R2=H) and derived from linear aliphatic aldehydes, has led to α-phenylselanyl hydrazones . α-Phenylselanyl nitriles were, however, isolated when an excess of base and of PhSeX (X=Cl, Br) were used. Hydrazones bearing an α-alkyl substituent (R2≠H) gave also nitriles . SAMP-hydrazones showed the same reactivity and the corresponding nitriles were obtained in a racemic form. The use of PhSCl, in the place of PhSeBr, has led to α-phenylsulfanyl nitriles from hydrazones derived from α-branched aldehydes (R2≠H).