“…However, the most convenient routes are based upon the Curtius rearrangement of azides 7 and the Bischler-Napieralski cyclization of biphenyl acetamide derivatives. 2,8 More reliable methods involving the rearrangement of polycondensed triazolyl derivatives, 9 the transformation of spiro-fluorenetriazolines by electrochemical means, 10 the photochemically induced or radical-mediated cyclization of 1,2diarylaminoethylenes, 1,11 the dehydromethoxylation of aminomethoxydihydrophenanthrenes 12 have been also reported. However, all these synthetic routes suffer from several drawbacks and genuinely lack universality.…”