First asymmetric total synthesis of Us-7 and -8, novel D-seco Corynanthe-type oxindole alkaloids from Uncaria attenuata: structure revision of Us-7 and determination of absolute stereochemistry.
[reaction: see text] Starting from (S)-glycidol, the asymmetric total synthesis of novel D-seco Corynanthe-type oxindoles Us-7 and Us-8 was accomplished. The structure of Us-7 was revised from the reported structure 1 with the (3R,7S) form to structure 22 with (3S,7R), and the absolute stereochemistry at C15 of both alkaloids was established.
Takayama
Hiromitsu
H
Graduate School of Pharmaceutical Sciences, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
Fujiwara
Rika
R
Kasai
Yasuko
Y
Kitajima
Mariko
M
Aimi
Norio
N