ALKYL-C VERSUS PHENYL-C REACTIVITY IN UNSYMETRICAL CYCLOPROPENONES. REACTION OF METHYLPHENYLCYCLOPROPENONE WITH PYRAZOLES.
Methylphenylcyclopropenone (1) reacts with pyrazole and 3,5-dimethylpyrazole to afford ketones (2) resulting from initial nucleophilic attack at methyl-C, in agreement with an AM1 calculation performed on 1.Intermediacy of dipolar species 3 accounts for p