Intramolecular Hetero-Diels-Alder Reaction of Vinylallenes and Imines: Synthesis of 9-Methyl-1,2,3,4,5,6,7,8-octahydroacridine

The intramolecular hetero-Diels-Alder reaction of vinyl­allenes and imines has been carried out. Depending on the substit­uents on the allene and the length of the tether linking diene and heterodienophile, the reaction proceeds thermally or with Lewis acid activation. The transformation of one of the adducts into a 9-substituted octahydroacridine is reported.