The central and conserved role of peptides in extant biology suggests that they played an important role during the origins of life. Strecker amino acid synthesis appears to be prebiotic, but the high pK aH of ammonia (pK aH = 9.2) necessitates high pH reaction conditions to realise efficient synthesis, which places difficult environmental constraints on prebiotic amino acid synthesis. Here we demonstrate that diamidophosphate reacts efficiently with simple aldehydes and hydrogen cyanide in water at neutral pH to afford N-phosphoro-aminonitriles. N-Phosphoro-aminonitrile synthesis is highly selective for aldehydes; ketones give poor conversion. N-Phosphoro-aminonitriles react with hydrogen sulfide at neutral pH to furnish aminothioamides. The high yield (73%-Quant.) of N-phosphoro-aminonitriles at neutral pH, and their selective transformations, may provide new insights into prebiotic amino acid synthesis and activation.