Steric acceleration of intramolecular oxime and hydrazone cycloadditions
Abstract
Selected conformational constraints, achieved by the incorporation of ortho-substituents in 2-substituted 1-allyloxybenzenes, where the substituent is a 1,3-dipole or its tautomeric precursor, as in oximes, can be employed to accelerate the 1,3-dipolar cycloaddition process. Some evidence that hydrazones preferentially react with the alkene group by prior oxidation to the corresponding nitrilimine species is presented.