Imino Diels-Alder reaction: Application to the synthesis of diverse cyclopenta[c]quinoline derivatives

Several unreported tetrahydrocyclopenta[c]quinoline derivatives have been p repared employing an imino Diels-Alder cycloaddition as the key ring formin g step. The tetrahydroquinoline 10 can be directly oxidized into the cyanoa mine 15 which upon treatment with LDA and propyl bromide is easily converte d into the propyl derivative. On direct treatment with NaBH4 in methanol th e reductive decyanation occurred, leading stereospecifically to 17.