The carbylamine reaction (also known as the Hoffmann isocyanide synthesis) is the synthesis of an isocyanide by the reaction of a primary amine, chloroform, and base. The conversion involves the intermediacy of dichlorocarbene. 
Illustrative is the synthesis of tert-butyl isocyanide from tert-butylamine in the presence of catalytic amount of the phase transfer catalyst benzyltriethylammonium chloride.
:MeCNH + CHCl + 3 NaOH → MeCNC + 3 NaCl + 3 HO
Similar reactions have been reported for aniline. It is used to prepare secondary amines.