A new and general synthetic pathway to strychnos indole alkaloids: total syntheses of (-)-dehydrotubifoline and (-)-tubifoline by palladium-catalyzed asymmetric allylic substitution.
[see reaction]. A novel procedure for the synthesis of an indole skeleton was developed. Treatment of a cyclohexenol derivative having a silyloxymethyl group at the 2-position with N-tosyl-o-bromoaniline in the presence of Pd2dba3*CHCl3 and (S)-BINAPO gave compound 6a with 84% ee in 75% yield. Compound 6a was converted into 11, which was treated with Pd(OAc)2 and Me(2)PPh in the presence of Ag2CO3 to give indoline derivative 12. From 12, we succeeded in the total syntheses of (-)-dehydrotubifoline and (-)-tubifoline.
Mori
M
M
Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan. mori@pharm.hokudai.ac.jp
Nakanishi
M
M
Kajishima
D
D
Sato
Y
Y
D000470:Alkaloids / Q000138:chemical synthesis*; D002384:Catalysis; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry; D019684:Magnoliopsida / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*
D000470:Alkaloids; D007211:Indoles; C431470:dehydrotubifoline; C431471:tubifoline; D010165:Palladium