Cadiot–Chodkiewicz coupling

The Cadiot–Chodkiewicz coupling in organic chemistry is a coupling reaction between a terminal alkyne and a haloalkyne catalyzed by a copper(I) salt such as copper(I) bromide and an amine base.

The reaction mechanism involves deprotonation by base of the terminal alkyne proton followed by formation of a copper(I) acetylide.

A cycle of oxidative addition and reductive elimination on the copper centre then creates a new carbon-carbon bond.

In one study[3] the Cadiot–Chodkiewicz coupling has been applied in the synthesis of acetylene macrocycles starting from cis-1,4-diethynyl-1,4-dimethoxycyclohexa-2,5-diene.

This compound is also the starting material for the dibromide through N-bromosuccinimide (NBS) and silver nitrate: The coupling reaction itself takes place in methanol with piperidine, the hydrochloric acid salt of hydroxylamine and copper(I) bromide.