摘要：

The stepwise route B from pagodanes to dodecahedranes was completed by double catalytic dehydrocyclization of saturated (alkylated) bisseco precursor substrates (2, 3, 5, 16). Based on pagodane, dodecahedranes (9, 10, 13, 14, 17) were obtained in up to 53% yield. Transannular C,C bond formation at the bisseco stage and partial (C–alkyl) or total (C–OR, C–CO₂R) removal of substituent groups under the necessarily forcing reaction conditions constituted preparative limitations. Attempts at alternative ring closure methodologies (homo-Norrish type II, homoenolization, carbene insertion) have remained unsuccessful.

展开