Palladium-Catalyzed Cross-Coupling of 4-Tosyloxyquinazolines with Organoindium Reagents: An Efficient Route to 4-Substituted Quinazolines

Abstract

An efficient route to 4-substituted quinazolines by arylation or alkylation of quinazolinones under mild conditions is described. 4-Tosyloxyquinazolines were obtained through the reaction of quinazolinones and p-methylbenzenesulfonyl chloride in the presence of K2CO3. The cross-coupling reaction of 4-tosyloxyquinazolines with organoindium reagents, carried out in tetrahydrofuran, catalyzed by Pd2(dba)3/ (2-furyl)3P led to the formation of 4-functionalized quinazolines in good to excellent yields. Higher yields were obtained by the one-pot reaction of quinazolinone, p-methylbenzenesulfonyl chloride, Pd2(dba)3-/(2-furyl)3P, and organoindium reagent. These methods using organoindium compounds as coupling partners provided an efficient route to 4-(hetero)aryl/alkylquinazolines, especially 4-substituted quinazolines bearing a halogen scaffold.