Synthesis of dimethyl gloiosiphone a by way of palladium-catalyzed domino cyclization.
The synthesis of a spiro[4.4]nonane skeleton by the palladium-catalyzed domino cyclization of a linear 7-methylene-2,10-undecadienyl acetate is described. The pi-allylpalladium intermediate underwent intramolecular alkene insertion with high intraannular diastereoselectivity, followed by intramolecular Heck-type cyclization, leading to a spiro[4.4]nonane system. Oxidation of the allylic ether moiety and transformation of the vinyl group to an exo-methylene unit provided 3, which is the known synthetic intermediate of dimethyl gloiosiphone A (2).
Doi
Takayuki
T
Department of Applied Chemistry, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-8552, Japan.
Iijima
Yusuke
Y
Takasaki
Masaru
M
Takahashi
Takashi
T