Organocatalytic double Michael reaction and the subsequent aldol condensation of (E)-7-oxooct-5-enal and 3-arylpropenal (e.g., cinnamaldehyde) provided octahydro-6-oxo-1-phenylnaphthalene-2-carbaldehyde in high diastereoselectivity and high enantioselectivity (>99% ee). Structures of the adducts 5a and 5j were confirmed unambiguously by X-ray analysis.