Stephen aldehyde synthesis

Not to be confused with Stevens rearrangement.

Stephen aldehyde synthesis, a named reaction in chemistry, was invented by Henry Stephen (OBE/MBE). This reaction involves the preparation of aldehydes (R-CHO) from nitriles (R-CN) using tin(II) chloride (SnCl2), hydrochloric acid (HCl) and quenching the resulting iminium salt ([R-CH=NH2]+Cl−) with water (H2O).[1] During the synthesis, ammonium chloride is also produced.

Overall, the reaction scheme is as follows:

Sonn-Müller method

In the Sonn-Müller method [2][3] the intermediate iminium salt is obtained from reaction of an amide PhCONHPh with phosphorus pentachloride.

References

  1. ↑ Stephen, H. (1925). "A new synthesis of aldehydes". J. Chem. Soc., Trans. 127: 1874–1877. doi:10.1039/CT9252701874.
  2. ↑ Sonn and Müller, Ber., 52, 1929 (1919).
  3. ↑ Jonathan W. Williams, Charles H. Witten, and John A. Krynitsky (1955). "o-Tolualdehyde". Org. Synth.; Coll. Vol. 3, p. 818