The reactivity of 3-methyl-4-nitro-5-styrylisoxazole with some bis-enolisable ketones

The expected Michael adducts and spiroisoxazolines are obtained from the reaction between 3-methyl-4-nitro-5-styrylisoxazole and bis-enolisable ketones. Contrary to reported data, Michael adducts are obtained in good yields only when a substoichiometric amount of base is used, whereas spiroisoxazolines were obtained as the major product when the base is present in a large excess. (C) 2002 Elsevier Science Ltd. All rights reserved.