Copper(I)-Mediated Cascade Reactions: An Efficient Approach to the Synthesis of Functionalized Benzofuro[3,2-d]pyrimidines

A novel cascade reaction was developed for the synthesis of diverse members of a series of benzofuro(3,2-d]pyrimidine derivatives. The process utilizes readily prepared 3-chlorochromenones and various commercially available amidines and their analogues as starting materials. This tandem reaction is promoted by using a simple copper(I) reagent and involves a chemoselective Michael addition-heterocyclization-intramolecular cyclization sequence.