Stereoselective construction of 2-vinyl 3-hydroxybenzopyran rings: total syntheses of teadenols A and B.
Total syntheses of teadenols A and B, isolated from fermented tea, were accomplished in a highly stereocontrolled manner. Key steps were an organocatalytic asymmetric α-aminoxylation reaction of an aldehyde and a palladium-catalyzed intramolecular allylic substitution with phenol. In the latter reaction, we utilized the different conformational preferences of cyclic and acyclic carbonate precursors to obtain cis- and trans-fused benzopyran rings, respectively, via intramolecular etherification.
School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan. kant@u-shizuoka-ken.ac.jp hamashima@u-shizuoka-ken.ac.jp.
Ryunosuke
R
Yoshida
School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan. kant@u-shizuoka-ken.ac.jp hamashima@u-shizuoka-ken.ac.jp.
Hitoshi
H
Ouchi
School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan. kant@u-shizuoka-ken.ac.jp hamashima@u-shizuoka-ken.ac.jp.
Atsushi
A
Yoshida
School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan. kant@u-shizuoka-ken.ac.jp hamashima@u-shizuoka-ken.ac.jp.
Tomohiro
T
Asakawa
School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan. kant@u-shizuoka-ken.ac.jp hamashima@u-shizuoka-ken.ac.jp.
Makoto
M
Inai
School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan. kant@u-shizuoka-ken.ac.jp hamashima@u-shizuoka-ken.ac.jp.
Masahiro
M
Egi
School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan. kant@u-shizuoka-ken.ac.jp hamashima@u-shizuoka-ken.ac.jp.
Yoshitaka
Y
Hamashima
School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan. kant@u-shizuoka-ken.ac.jp hamashima@u-shizuoka-ken.ac.jp.
Toshiyuki
T
Kan
D001578:Benzopyrans / Q000737:chemistry*; D002384:Catalysis; D060326:Chemistry Techniques, Synthetic; D010165:Palladium / Q000737:chemistry; D010636:Phenols / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism
D001578:Benzopyrans; D010636:Phenols; D010165:Palladium