Formal [4+2] cycloaddition of quinolines, pyridines, and isoquinolines with 3-ethoxycyclobutanones

3-Ethoxycyclobutanones reacted with pyridines, quinolines, and isoquinolines to give the corresponding formal [4+2] cycloadducts, 9a-hydro-2H-quinolizin-2-one derivatives, by using Me3SiOTf in acetonitrile. Cycloaddition of 3-ethoxy-2-monoalkylcyclobutanones to 5-nitroquinoline or 4-cyanopyridine proceeded stereoselectively. (C) 2016 Elsevier Ltd. All rights reserved.