1,3-DIPOLAR CYCLOADDITION OF ETHYL DIAZOACETATE WITH (E)-3-ARYLIDENECHROMAN-4-ONES. A NEW ACCESS TO SPIROCYCLOPROPANE DERIVATIVES

Dipolarophiles (I) react with ethyl diazoacetate (II) at the exocyclic double bond of (I), regardless of the electronic nature of the p-substituents on the aryl group of (I), to provide the single spiro-compounds (III).