Regioselective synthesis and side-chain metallation and elaboration of 3-aryl-5-alkylisoxazoles

A number of 3-aryl-5-alkylisoxazoles have been synthesized in high yields by reacting arylnitrile oxides with free enolate ions regioselectively obtained by metallation of various alkyl methyl ketones with LDA in THF at −78°C followed by dehydration. Investigations concerning regioselective side-chain metallation and elaboration of one of them (3-phenyl-5-ethylisoxazole) have also been carried out.