Electrophilic addition of 1-(1-cyclohexenyl)-1-cyclopropanol trimethylsilyl ether to α,β-unsaturatedaldehyde acetals under Lewis acidic conditions proceeds with good to excellent diastereoselectivity toafford spirocyclobutanones containing three contiguous stereocenters. A convenient entry to enantioselective syntheses is available by use of a nonracemic C2-symmetric acetal. Elaboration of the resultingadducts provides ready access to medium-sized carbocycles.