How to name this cyclic compound with an O in it?
I was going to name it cyclobutane, but not all of the atoms making up the ring are carbons, one is an oxygen. So, then I decided to name it butane, but that doesn't make sense because there is a ring.
Well, the molecule you draw is tetrahydrofuran, aka THF, but of course the only way you can guess that is if you already know the molecule. It's a very common organic solvent.
If you didn't know its common name, you could try to name it according to IUPAC nomenclature. It's an ether, and it's cyclic, so it can be named as oxacyclopentane. But IUPAC has specific names for cyclic ethers, which in this case is oxolane:
(from this organic chemistry book).
