DIELS-ALDER REACTION OF ANTHRACENO[3.3]ORTHO-BENZOPHANE AND ANTHRACENO[3.3]ORTHO-NAPHTHOPHANE - CONTROL OF PI-FACIAL DIASTEREOSELECTIVITY BY UNDERLYING PI-SYSTEMS

Dimethyl acetylenedicarboxylate, 1-phenyl-1,2,4-triazoline-3,5-dione a nd dimethyl azodicarboxylate cycloadded to benzo[3.3]orthoanthracenoph ane 1a and naphtho derivative 1b preferably from the outside-face of 1 . On the other hand, the inside-face is the more favorite site in Diel s-Alder reactions of 1 with maleic anhydride, maleimide, N-tert-butylm aleimide and N-phenylmaleimide. Naphthophane 1b is more pi-face-select ive than benzophane 1a. Electrostatic and steric interactions between the facing aromatic ring of 1 and a dienophile are considered to contr ol the pi-facial selectivity in the reactions mentioned above. Copyrig ht (C) 1996 Elsevier Science Ltd