A Combination of Tandem Amine-Exchange/Heterocyclization and Biaryl Coupling Reactions for the Straightforward Preparation of Phenanthro[9,10-<i>d</i>]pyrazoles
The tandem amine-exchange/heterocyclization of enaminoketones is successfully applied to the regioselective preparation of a series of new 4,5-diarylpyrazoles by reaction of phenylhydrazine and several 3-N,N-(dimethylamino)-1,2-diarylpropenones. The comparison of a vast array of biaryl coupling procedures provides general, complementary approaches to new phenanthro[9,10-d]pyrazoles. The most efficient