Biodiversity (BI131), Evolution and Diversity (BI164), Comparative Vertebrate Anatomy (BI276), Vertebrate Natural History (277), Animal Behavior (BI373), Behavioral and Physiological Ecology (BI452)

The Katz Group explores the synthesis of complex aryl ether and aryl amine macrocycles. Our favorite targets are aza- and oxacalixarenes and related cyclophanes, generated by condensation of diphenols, diaminobenzenes, and/or aminophenols with dihalogenated aromatics. We strive for chemical and operational simplicity; the representative examples shown below are all compounds produced in either a single step (2-component macrocycles) or one-pot manner (3-component macrocycles). We continue to explore properties and applications of these and other accessible ring systems. Oxacalix[2]arene[2]naphthyridines are promising substrates for molecular recognition applications. In the observed three dimensional architecture, the naphthydridine rings create a cavity with spacing of approximately 7.0 Å between the co-parallel nucleophilic component rings, creating a new class of "molecular tweezers". These substrates have shown selectivity for host-guest binding of neutral and charged aromatic compounds in organic solution. Modification of the framework with fluorophores allows for visual detection of organic analytes. The Katz group has shown that a variety of previously unknown poly(meta-phenylene oxides) can also be formed using SNAr methods. The success of the polymerization is electrophile-specific, and our Macromolecules manuscript details that differences in chain conformation dictate the resulting kinetic product distributions. We are exploring the synthetic scope of materials available by our method, and investigating applications of poly(mPOs). Acetylenes are increasingly versatile functional groups for a range of complexity-building organic transformations and for the construction of desirable molecular architectures. The Katz group is exploring alkynes as electron withdrawing groups (EWG) for promoting nucleophilic aromatic substitution (SNAr) reactions. We have recently published that even a single ethynyl group is sufficient to allow substitution of fluorobenzenes by phenol, alcohol, and aniline nucleophiles. Ortho-fluoroacetylenes also have the ability to undergo tandem substitution-anionic cyclization to produce heterocyclic compounds.