They can be synthesized intramolecularly from propyl sidechains in the Yang reaction, and difluorodihaloethylene reacts with alkenes and alkynes to produce this molecule. Metallo versions of it are key intermediates in ring closing metathesis reactions, while silyl versions of make better catalysts 
They can be synthesized intramolecularly from propyl sidechains in the Yang reaction, and difluorodihaloethylene reacts with alkenes and alkynes to produce this molecule. Metallo versions of it are key intermediates in ring closing metathesis reactions, while silyl versions of make better catalysts than other alkanes in Hiyama coupling due to enhanced Lewis acidity. It can be synthesized in the presence of a strong base from malonic ester and 1,3-propyl dihalides. Beta-lactams contain it, but with a nitrogen atom replacing one of its carbon atoms. If this molecule has two double bonds, it becomes antiaromatic. For ten points, name this cyclic alkane with formula C4H8, often depicted as a square.
They can be synthesized intramolecularly from propyl sidechains in the Yang reaction, and difluorodihaloethylene reacts with alkenes and alkynes to produce this molecule.