摘要:
Aromatic o-formyl acetals undergo base-catalyzed Claisen-Schmidt condensation with nitro compounds, ketones, methyl acetate, and acetonitrile to produce functionalized styrenes. Hydrolysis of the acetal and cyclization of the product in methanol provide methoxy phthalans 8 which are used to generate isobenzofurans bearing a functionalized substituent at C-1. The Diels-Alder reactions of these isobenzofurans with several dienophiles have been studied. Conjugated exo-methylene phthalans 20 have been isolated, and an unusual elimination of nitrous acid from nitroalkyl phthalans 8E and 8F has been observed.