1,4-Dichlorobut-2-ene

1,4-Dichlorobut-2-ene are organochlorine compounds with the formula. Cis and trans isomers exist. These compounds are intermediates in the industrial production of chloroprene. They are main impurity in technical grade chloroprene.

Synthesis and reactions

1,4-Dichlorobut-2-ene are produced by chlorination of butadiene:
It is isomerized to 3,4-dichlorobut-1-ene by heating to temperatures of 60–120 °C in the presence of a catalyst:
The resulting 3,4-dichlorobut-1-ene is a precursor to chloroprene, the monomer for the synthetic rubber neoprene.
1,4-Dichlorobut-2-ene is a precursor to various heterocycles. The -isomer is also one of the starting materials for the poriferic natural product sceptrin.