(C) The subregions of a glycerophospholipid molecule; phosphatidylcholine is shown as an example. The hydrophilic head is composed of a choline structure (blue) and a phosphate (orange).

Trimerization of commercially available coprostanone (a steroid ketone with a cis A/B ring junction) by treatment with titanium tetrachloride yields this unusual, chiral, cleft-containing molecule.