Synthesis of Functional meso-Aryl Porphomonomethenes and Porphodimethenes: Application to the Preparation of a Chiral Calixphyrin Dimer
2004-11-12T00:00:00Z (GMT) by
Reaction of 5,5-dimethyldipyrromethane (1) with electron-deficient aryl aldehydes in the presence of BF3−Et2O and NH4Cl in propionitrile constitutes efficient, easy access to unprecedented, functional porphomonomethenes together with the expected porphodimethenes (calixphyrins). Alternatively, when the reaction was carried out in CH2Cl2 in the presence of an acid and Florisil, the expected bis-arylcalixphyrin was isolated in 41% yield, while no scrambled macrocycle was detected. After reduction of the nitro function, porphomonomethene 9 was efficiently condensed with the binaphthyl diacyl chloride (10) leading to the first chiral calixphyrin dimer (11) that exhibits a moderate enantiorecognition toward the enantiomers of malic acid.