Benzisoxazoles: new routes to coleophomone analogues

This project has been part of an ongoing interest in metabolites with a cyclic tricarbonyl motif 1, usually enolised. Coleophomones A C have a unique architecture with the cyclic tricarbonyl motif embedded in an 11-membered ring: A & B exist in aldol equilibrium, B & C are geometric isomers, and D lacks the macrocycle.1,2 Antifungal & antibiotic activity, and inhibition of human heart chymase & bacterial cell-wall transglycosylase, has generated synthetic interest. In an approach distinct from reported studies,3 we propose 4-carbonyl-substituted isoxazoles, from dipolar cycloaddition of nitrile oxides, as building blocks for the tricarbonyl framework. During this investigation precursors to the macrocycles of coleophomones A, B, C and analogues were developed. En route to these precursors we have uncovered and probed a facile and highly unusual benzisoxazole to oxazole rearrangement. *Schemes and figures relating to the abstract can be found within the document proper.