p. 139-143
Complanadine A was isolated from club moss Lycopodium complanatum by J. Kobayashi group. Its structure was characterized by a dimeric motif of lycodine-type C_<16>N_2 skeleton. So far complanadines B, D and E, which consist of the lycodine skeleton, were also reported as dimeric Lycopodium alkaloids. Interestingly complanadines A, B, D, and E induced mRNA expression level for nerve growing factor (NGF) in 1321N1 human astrocytoma cells. Because of the intriguing biological activity and complex structure, we started a synthetic program toward complanadines. The total syntheses of lycodine (5), complanadines A (1) and B (2) are described. For synthesis of lycodine, notable transformations include diastereoselective Diels-Alder and Mizoroki-Heck reactions to access a bicycle[3.3.1]nonane core in the lycodine skeleton. In the total syntheses of complanadines, C-H functionalization of pyridine N-oxide is a key feature for construction of the dimeric structure. Further synthetic studies toward natural enantiomer of complanadines as well as biological studies are now in progress, the results will be discussed in the presentation.