Isocomene is a sesquiterpene first isolated from the perennial herb southern goldenbush (Isocoma wrightii),[1] from which it derives its name.

Its unusual structure consisting of three fused cyclopentane rings was first described by Zalkow et al. in 1977.

[1] The first total synthesis of isocomene was published by M.C.

Pirrung in 1979.

[2] The key steps are a photocatalyzed intramolecular [2 + 2] cycloaddition reaction followed by a rearrangement reaction which forms three contiguous chiral centers.