In the Strecker synthesis, one starts with an aldehyde, ammonium chloride (NH4Cl), and potassium cyanide (KCN).
Note ↑: The carbonyl carbon of an amide is sp2
hybridized and has trigonal planar geometry. A second
resonance structure can be drawn that delocalizes the nonbonded electron pair on the N atom.
Amides are more resonance stabilized than other acyl compounds, so the resonance structure
having the C=N makes a significant contribution to the hybrid.