Sequential Rearrangements and Unusual Isomerization with KOtBu: Synthesis of anti-12-Vinyltricyclo[6.3.1.02,7]dodeca-2,4,6,9-tetraene and its Derivatives

The reaction of alcohol 13a with SOCl2 gave 13b, 14a and 15a, and the reaction of chloride 13b with AgNO3 (in MeO−/MeOH) gave 13c, 14b and 15b. In these reactions, 14a, 14b, 15a and 15b are the major products by sequential rearrangements. Treatment of the rearranged products 14a and 15a with KOtBu (potassium tert-butoxide) gave 18 by an unusual isomerization. Compounds 19, 20 and 21 were also synthesized in different reactions. Compounds 14, 15, 19, 20 and 21 are all derivatives of anti-12-vinyltricyclo[6.3.1.02,7]dodeca-2,4,6,9-tetraene 19, and the syntheses of 19, 20 and 21 support the structures of compounds 14, 15 and 18.