Diels-Alder reaction of anthraceno[3.3]ortho-benzophane and -naphthophane. Control of π-facial diastereoselectivity by underlying π-systems

Dimethyl acetylenedicarboxylate, 1-phenyl-1,2,4-triazoline-3,5-dione and dimethyl azodicarboxylate cycloadded to benzo[3.3]orthoanthracenophane 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 Diels-Alder reactions of 1 with maleic anhydride, maleimide, N-tert-butylmaleimide and N-phenylmaleimide. Naphthophane 1b is more π-face-selective than benzophane 1a. Electrostatic and steric interactions between the facing aromatic ring of 1 and a dienophile are considered to control the π-facial selectivity in the reactions mentioned above.