Synthesis and characterization of coronanes: Multicyclopropane-fused macrocyclic arrays

Stepwise macrocyclization of the all syn-trans-1,15-quinquecyclopropanedimethanol (4) with iso- and terephthaloyl chlorides and 4,4'-methanediyl-dibenzoic acid (28) gave the corresponding coronanes 22, 23, and 32. The same protocol was used with all syn-trans-1,21-septecyclopropanedimethanol (5) and 2,3-naphthalenedicarboxylic acid to obtain the macrolide 27. Direct macrocyclization of diol 4 and 1,10-phenanthroline-2,9-dicarbonyl chloride (33) and 2,2'-bipyridine-4,4'-dicarbonyl chloride (35) gave the coronanes 34 and 36, respectively. Ring closing metathesis (RCM) of the diene 42 using Cl-2(Cy3P)(2)Ru=CHPh (48) (Grubbs's catalyst) gave the macrocyclic lactone 45. The structures of coronanes 22, 23, 32, 34, 36, and 45 were confirmed by X-ray crystallographic studies which showed the cyclopropyl chain to adopt very differing conformations throughout the series. Several of the macrocycles have significant free pathways through their ring centers, and in the case of compound 34 there is a water molecule hydrogen bonded within the ring. This latter compound has the potential to act as a chiral ligand to metal centers.