A Study On The Acid-catalyzed Ring-opening Cascade Reactions Of Alkyl 2-aroyl-1-Phenoxycyclopropanecarboxylates

Owing to the strain structure of the molecule,the cyclopropane tends to proceed a ring-opening reaction to release the stretching force.Among this,the D-A cyclopropane which is a highly activated cyclopropane has been used as an agent to bulid carbocyclic and heterocyclic skeletons.So,synthesizing structurally special D-A cyclopropanes has been an attractive subject for chemists.Recently,a special D-A cyclopropane was obtained during our researching on the cyclopropene.We were interested in the studying of it because of its special structure.Based on the investigation of our group,we did some research on the application of methyl 2-aroyl-1-phenoxycyclopropanecarboxylates as a four-membered synthon in organic synthesis.1)Firstly,we did an exploration of the reaction between methyl2-aroyl-1-phenoxycyclopropanecarboxylates and aromatic amines.To our surprise,the reaction could proceed smoothly and afforded highly functionalized pyrroles as the only product.Then we were focused on the optimization of the reaction conditions according to the results and the products were obtained in a very good yield(up to 98%)under the optimized conditions.With the optimized conditions at hand,we investigated the scope of the reaction.2)Then the reaction of methyl 2-aroyl-1-phenoxycyclopropanecarboxylates and indoles in the presence of aluminium chloride was studied.We were glad to find that the multi-substituted carbazole derivatives were afforded in a pretty good yield(up to 83%).Based on the findings,we examined the scope of the reaction and proposed the possible mechanism.3)What’s more,we studied the reaction of phenylhydrazines and methyl2-aroyl-1-phenoxycyclopropanecarboxylates.The result indicated that 1-(phenylamino)-1H-pyrrole could be afforded in moderate yields.