NHC-catalyzed [12+2] reaction of polycyclic arylaldehydes for access to indole derivatives.

An N-heterocyclic carbene (NHC) catalyzed enantio- and diastereoselective [12+2] cycloaddition is disclosed to rapidly construct sophisticated molecules bearing a tricyclic core and morpholine moiety. The success of our reaction relies on the NHC-catalyzed remote sp 3 (C-H) bond activation of a 5 H -benzo[ a ]pyrrolizine-3-carbaldehyde under oxidative conditions. Preliminary studies revealed that our products exhibit superior in vitro bioactivities against two plant pathogens to commercial Bismerthiazol (BT) and Thiodiazole Copper (TC).