Can anyone help me?? I want to ask what is stephen`s reduction.

The synthesis of aldehydes by the treatment of nitriles with anhydrousstannous chloridesaturated with dry hydrogen chloride gas to form crystalline “aldimine stannichloride” followed by their hydrolysis with water is generally referred to as the Stephen reaction. The study finds that the success of this reaction is based on the precipitation of the ether insoluble crystalline “aldimine stannichloride” (i.e., (RCH=NH·HCl)2SnCl4). It has been found that this reaction in general is more feasible for aromatic nitriles instead of the aliphatic nitriles. This reaction is considered useful for the preparation of aldehydes.

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.