Total synthesis of (+/-)-flustramines A and C, (+/-)-flustramide A, and (-)- and (+)-debromoflustramines A.
Here we describe the efficient total synthesis of the three title hexahydropyrrolo[2,3-b]indole alkaloids and debromo derivative from readily available indolin-3-ones using key domino reactions, olefination-isomerization-Claisen rearrangement (OIC), and reductive cyclization (RC). (+/-)-Flustramine C (5) was synthesized in five steps from 6-bromoindolin-3-one 9 via a key intermediate 13a. (+/-)-Flustramine A (1) has been obtained by reduction of flustramide A (6), which has been prepared in five steps from 13a. (+/-)-Debromoflustramine A (19) was provided in a similar manner from 13b. The (-)- and (+)-enantiomers of 19 were synthesized through optical resolution of (+/-)-carboxylic acid 17b using (R)-4-phenyloxazolidin-2-one.
Kawasaki
Tomomi
T
Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan. kawasaki@my-pharm.ac.jp
Shinada
Masashi
M
Ohzono
Mayu
M
Ogawa
Atsuyo
A
Terashima
Romi
R
Sakamoto
Masanori
M
D017605:Bromine Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D026121:Indole Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure
D017605:Bromine Compounds; D026121:Indole Alkaloids; C519054:flustramide A; C511648:flustramine C