SYNTHESES OF NOVEL GYROCHIRAL PENTACYCLIC SYSTEMS WITH C2 SYMMETRY - (-)-C2-BISMETHANOTWISTANE AND (+/1)-C2-METHANODITWISTANE

Diazomethane ring expansion of C2-bismethanotwistane-8, 12-dione (18) obtained from the cyclohexadiene-benzoquinone adduct 10 was explored to secure the synthetic route to a novel gyrochiral pentacyclic system, D3-tritwistane (7). Whereas D3-trishomocubanedione (22) was found to afford the single 23 and the double 24 ring expansion products, 18 failed to yield the expected doubly expanded product with aD3-tritwistane system. Preparation of the new gyrochiral pentacyclic hydrocarbons (-)-C2-bismethanotwistane (5) and (±)-C2-methanoditwistane (6) are reported. © 1979, American Chemical Society. All rights reserved.