Chiral Polyaryl Cyclophanes

A series of propeller‐shaped, C 3 ‐symmetric cyclophanes have been synthesized by the macrocyclization of 1,3,5‐trimercaptobenzene ( 12 ) with either a tris[ o ‐(halomethyl)aryl]phosphine (e.g. 11 ) or a tris[ o ‐(halomethyl)aryl]benzene (e.g. 24 ). Two phosphine‐capped cyclophanes ( 5 and 6 ) were prepared in this way; they proved to be configurationally stable, and both were resolved into pure enantiomers by supercritical fluid chromatography on chiral supports. Compound 6 , in particular, displayed a large specific rotation ([ α ] D ≈ 800) and strong circular dichroism. The one triarylbenzene‐capped cyclophane ( 9 ) that was made possessed a modest barrier to racemization (Δ G rac ‡ = 15.7 kcal/mol). Computational studies of the trends in optical rotation for this class of compounds as well as the pathway for the racemization of 9 are also reported.