Scheme 2.

Synthesis of ethanoanthracenes 13a–n (Series I, Table 1), 14a–c (Series II, Table 1), 16a–n (Series IIIA, Table 2), 17a–n, 18 (Series IIIB, Table 3): Reagents and conditions (a) Toluene, 90 °C, 48 h.