A novel and convenient synthesis of 5-aryl-4-bromo-3-carboxyisoxazoles: useful intermediates for the solid-phase synthesis of 4,5-diarylisoxazoles

A novel synthesis of 5-aryl-4-bromo-3-carboxyisoxazoles employing a [3+2] cycloaddition of a nitrile N-oxide with 2-aryl-1-bromoalkynes as the key step is described. The utility of these 5-aryl-4-bromo-3-carboxyisoxazoles in the solid-phase synthesis of 4,5-diarylisoxazoles is demonstrated.