Photochemistry of 4-(2‘-Aminoethyl)quinolones: Enantioselective Synthesis of Tetracyclic Tetrahydro-1a H -pyrido[4‘,3‘:2,3]- cyclobuta[1,2- c ] Quinoline-2,11(3 H ,8 H )-diones by Intra- and Intermolecular [2 + 2]-Photocycloaddition Reactions in Solution