Expeditious access of chromone analogues: via a Michael addition-driven multicomponent reaction

A Michael addition-driven four-component reaction (4-CR) was developed for derivatizing chromones by strategically suppressing competing 4-CR Ugi reaction without a catalyst. A series of structurally diverse 4-oxochroman-2-carboxamides was synthesized with this one-pot protocol. In addition, the new reaction was expanded for the synthesis of a series of tetrazole substituted chromones by replacing carboxylic acid with trimethylsilyl azide (TMSN₃). The imine functional group and the corresponding aldehyde hydrolysed from the imine were utilized for further structural diversification.