Dichlorocarbene is most commonly generated by reaction of chloroform and a base such as potassium tert-butoxide or aqueous sodium hydroxide.

In this conversion, a dichloromethane solution of a primary amine is treated with chloroform and aqueous sodium hydroxide in the presence of catalytic amount of the phase-transfer catalyst.

Illustrative is the synthesis of tert-butyl isocyanide:[7] In 1835, the French chemist Auguste Laurent recognised chloroform as CCl2•HCl (then written as C8Cl8•H4Cl4)[a] in his paper on analysing some organohalides.

Laurent also predicted a compound seemingly consisting of 2 parts dichlorocarbene which he named Chlorétherose (possibly Tetrachloroethylene, which was not known to exist at the time.

)[8] Dichlorocarbene as a reactive intermediate was first proposed by Anton Geuther in 1862 who viewed chloroform as CCl2.HCl[9] Its generation was reinvestigated by Hine in 1950.