Reaction of a Trifluoromethylated N-Monosubstituted Hydrazone with alpha,beta-EthenyI Ketones; A Novel Synthesis of Substituted Pyrazolidines and Pyrazolines

摘要

We hereby describe an instance of diastereoselective tri-fluoromethanesulfonic acid catalyzed 1,3-dipolar cycloaddition of a trifluoromethylated azomethine inline with alpha,beta-ethenyl ketones. Using two different reaction conditions, reaction of trifluoroacetal-dehyde phenylhydrazone and chalcone derivatives gave polysubsti-tuted pyrazolidines and pyrazolines derivatives with efficiency and high diastereoselectivity.