The highly diastereoselective synthesis of substituted 1,2,3,4,4a,9,9a,10-octahydroacridines 7, 8 with five stereogenic centers has been achieved by domino imine condensation/intramolecular polar [4π+ + 2π]-cycloaddition of anilines 3 and ω-unsaturated aldehydes 4. The transformations which can be performed under mild reaction conditions using 0.3 eq. BF3·Et2O as a Lewis acid give the cycloadducts 7, 8 with yields ranging from 63–76%. The relative configuration of 7, 8 was assigned by 1H- and 13C-NMR spectroscopy. For 7a, an X-ray crystal structure analysis was obtained. Experimental as well as semiempirical results support a polar [4π+ + 2π]-cycloaddition under kinetic control. It is assumed that the diastereoselectivity of the process is governed by decalin-like exo-E-anti-transition state structures 24, 25 with equatorial arrangement of the bulky substituents R2.