[3+3] Annulation via Ring Opening/Cyclization of Donor-Acceptor Cyclopropanes with (Un)symmetrical Ureas: A Quick Access to Highly Functionalized Tetrahydropyrimidinones

A mild and straight-forward access to pharmacologically privileged tetrahydropyrimidinones exploiting readily available Donor-Acceptor cyclopropanes (DACs) is reported. This methodology involves the Lewis acid catalyzed synthesis of uriedo-malonates from (un)symmetrical ureas and DACs followed by I-2-base mediated cyclization to their corresponding tetrahydropyrimidinones. The cyclization protocol involves nucleophilic attack of the nitrogen of urea on the newly generated electrophilic acceptor end of DAC. The post functionalization offered potential biologically active molecules.