Regioselective synthesis of functionalized pyrazole-chalconesviaa base mediated reaction of diazo compounds with pyrylium salts

A base-mediated reaction of triaryl/alkyl pyrylium tetrafluoroborate salts with α-diazo-phosphonates, sulfones and trifluoromethyl compounds affords the corresponding functionalized pyrazole-chalcones as 5-P-5 and 3-P-3 tautomeric mixture.