Skeletal rearrangement of O-propargylic formaldoximes by a gold-catalyzed cyclization/intermolecular methylene transfer sequence.
Skeletal rearrangement of O-propargylic formaldoximes, in the presence of gold catalysts, afforded 4-methylene-2-isoxazolines in good to excellent yields by an intermolecular methylene transfer. In addition, the cascade reaction with maleimide in the presence of a gold catalyst afforded isoxazole derivatives by cyclization/methylene transfer and a subsequent ene reaction, whereas that using a copper catalyst gave oxazepines through a 2,3-rearrangement.
Research and Analytical Center for Giant Molecules, Graduate School of Science, Tohoku University, 6-3 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8578 (Japan). itaru-n@m.tohoku.ac.jp.
Itaru
I
Nakamura
Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578 (Japan).
Shinya
S
Gima
Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578 (Japan).
Yu
Y
Kudo
Research and Analytical Center for Giant Molecules, Graduate School of Science, Tohoku University, 6-3 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8578 (Japan).|Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578 (Japan).
Masahiro
M
Terada
copper; gold; heterocycles; rearrangements; synthetic methods