Thermal and Photochemical Reactions of 10-Oxabenzo-syn-sesquinorbornene (1,2,3,4,9,10-Hexahydro-9,10-exo-epoxy-1,4-exo-methanoanthracene)

Article abstract of DOI:10.1021/jo00178a009

The chemical behavior of the title compound (5) is influenced both by the fused benzo group and by the oxa bridge.In thermal additions to the double bond 5 is from 1.3 to 13.7 times as reactive as the analogue 6 with CH2 in place of the O bridge.Treatment of the oxa compound 5 with chloroform and 50percent sodium hydroxide for 12 h yielded the crowded dichlorocarbene adduct to the double bond, while no way has been found to add dichlorocarbene to methylene species 6.The photochemical behavior of 5 in acetone resembles that of the parent syn-sesquinorbornene, 1.The benzo group also enables 5 by direct photoexcitation to capture hydrogen from cyclohexane, which 1 cannot do without a sensitizer.As a consequence of this direct excitation, 5 undergoes rapid rearrangement which competes with its other photochemical reactions.X-ray crystallographic studies of compound 5 and its dichlorocarbene adduct have been made and will be published seperately.