Ozonation of pentaphene (1) in methylene chloride at-78'with 1 mole equiv of ozone led to a peroxidic mixture which on reductive work-up (sodium iodide in acetic acid) gave 2, 2'- binaphthyl-3, 3 '-dicarboxaldehyde (5, 25%); oxidative work-up (sodium hydroxide, hydrogen peroxide) led to 5 (16'%), phthalic acid (8, 2%), and 2, 2'-binaphth: yl-3, 3'- dicarboxylic acid (9, 16%). Dialdehyde 5 was also obtained from 1 via osmium tetroxide ...
