Diastereoselective [3 + 2] Cycloaddition of Quinoxalin-2(1<i>H</i>)-ones with Donor–Acceptor Cyclopropanes: Efficient Synthesis of Tetrahydro pyrrolo[1,2-<i>a</i>]quinoxalin-4(5<i>H</i>)-ones
Himangsu Sekhar Dutta, Gulraız Ahmad, Afsar Ali Khan, Mohit Kumar, Raziullah, Jayanti Vaishnav⧧, Manoj Kumar Gangwar, Ravi Sankar Ampapathi⧧, Dipankar Koley
Abstract
A ytterbium triflate-catalyzed diastereoselective [3 + 2] cycloaddition of quinoxalinones with donor-acceptor cyclopropanes and cyclobutanes is described. A series of tetrahydropyrrolo-quinoxalinone derivatives were obtained in high yields (up to 96%) with excellent diastereoselectivities (up to 46:1). Other medicinally important heterocycles like benzoxazinone, isoquinoxalinone, and dibenzoxazepine derivatives were also suitable for the desired annulation reaction. The current method is applicable for the scale-up reaction. Further, the utility of this annulation reaction is demonstrated by the synthesis of densely functionalized proline derivatives.