Cadiot–Chodkiewicz coupling

The Cadiot - Chodkiewicz coupling reaction is a chemical which is used in organic chemistry for coupling terminal alkynes of two to diynes. The reaction is catalysed by copper salts. The reactants of terminal alkyne and a bromoalkyne are required. The Cadiot - Chodkiewicz coupling is a further development of the Glaser coupling and thus also related to the Hay coupling and the Eglinton coupling.

Reaction mechanism

The course of the reaction starts from the terminal alkyne. It is first associated with the copper (I ) ion by forming a π - complex. He said this caused considerable electron deficiency at the alkyne of the pKa value of about 30 is lowered to below 9. Through this so-called activation of the alkyne can be deprotonated in the subsequent step. Thereto bases such as triethylamine are used. Simultaneously, a copper (I) organic compound to which is added the bromoalkyne oxidative forms. The thus formed little stable copper ( III) compound decomposes in a fast subsequent step by reductive elimination to the deen and copper ( I) bromide, which is the association of a new terminal alkyne available. In this manner the catalyst is restored.