ChemInform Abstract: Ruthenium Porphyrin Catalyzed Three-Component Reaction of Diazo Compounds, Nitrosoarenes, and Alkynes: An Efficient Approach to Multifunctionalized Aziridines.
An efficient approach for the synthesis of pyrazolopyridines containing the aminochromane motif through a base-catalyzed cyclization reaction is reported. The synthesis was carried out through a three-component reaction of (arylhydrazono)methyl-4H-chromen-4-one, malononitrile, primary amines in the presence of Et3N at room temperature. However, carrying out the reaction under the same conditions without base led to a fused chromanyl-cyanopyridine. High selectivity, high atom economy, and good to high yields in addition to mild reaction conditions are the advantages of this approach.
Acatalytic dearomative three-component reaction of bromoarenes with TMS-diazomethane and allyl borate was developed. The key of this assembling reaction is the use of a diazo compound to generate a Pd-π-benzyl intermediate through a Pd-carbenoid species. This method allowed for a dearomative functionalization using arenes as limiting reagents. Heteroaryl bromides were also applicable to give dearomatized structures under the reaction conditions.
Efficient synthesis of pyrazolopyridines containing a chromane backbone through domino reaction
