Ketones containing alkene and alkyne units are often called unsaturated ketones. Generally the substrate will be an alkene or alkyne. Khand reactions, where the starting material contains both the alkene and alkyne moieties, are possible. The hydrohalogenation of alkyne is much slower than the alkene. Ozonolysis is the cleavage of an alkene to carbonyl compounds. When treated with a strong base many alkyl chlorides convert to corresponding alkene. The ether then decomposes into an alkene and an alkoxide. Natta catalysts used in alkene polymerization. It is a four-carbon branched alkene (olefin), one of the four isomers of butylene. Ethylene is a fundamental ligand in transition metal alkene complexes. Grubbs' catalyst is used for alkene metathesis. The epoxides are prepared by epoxidation of the alkene. Dihydrocinnamaldehyde is produced by the selective hydrogenation of the alkene subunit. The reaction results in an anti-Markovnikov addition of a thiol compound to an alkene. The ylide 8 is reacted with an aldehyde to produce the alkene 9.