Tetramethylethylene

Tetramethylethylene is a hydrocarbon with the formula Me2C=CMe2 (Me = methyl). A colorless liquid, it is the simplest tetrasubstituted alkene.

Synthesis
It can be prepared by base-catalyzed isomerization of 2,3-dimethyl-1-butene. Another route involves direct dimerization of propylene. It can also be produced by photolysis of tetramethylcyclobutane-1,3-dione.

Reactions
Tetramethylethylene forms metal-alkene complexes with low-valent metals and reacts with diborane to give the monoalkyborane known as thexylborane.

Oxidation gives pinacol.

It is a precursor to the herbicide fenpropathrin.