4-Chloro-2-pentene

4-Chloro-2-pentene is an organic compound with the formula C5H9Cl. Its molecule is a linear chain of five carbon atoms, with a double bond between carbons 2 and 3 and a chlorine attached to carbon 4.

Physical and chemical properties
At room temperature, 4-chloro-2-pentene is a liquid with a density of ca. 0.9 g/cm3 and a boiling point of 97 °C.

Synthesis
4-Chloro-2-pentene can be synthesized from its corresponding alcohol (3-pentene-2-ol) or from 1,3-pentadiene. In the latter case, 4-chloro-2-pentene can be obtained with a yield of 97%.

Uses
4-Chloro-2-pentene has been used to prepare quaternary ammonium salts based on N,N,N,N-tetramethyldiaminomethane, an intermediate in the manufacture of ionol (2,6-di-tert-butyl-4-methylphenol).

4-Chloro-2-pentene readily reacts with stannyl lithium at low temperature to provide respective allyl stannanes. Likewise, allyl silanes can be prepared from 4-chloro-2-pentene by silylation of the corresponding Grignard reagents with an appropriate chlorosilane.