Synthesis of diversely functionalized hexahydropyrrolo[2,3-b]indoles using domino reactions, olefination, isomerization and Claisen rearrangement followed by reductive cyclization.
Hexahydropyrrolo[2,3-b]indoles 6 were synthesized in five steps from indolin-3-one 8 by a general and efficient method, in which elements of molecular diversity were readily added onto the 3a-position of the pyrrolo[2,3-b]indole ring system. Horner-Wadsworth-Emmons reaction of 2-allyloxyindolin-3-ones 7, derived from indolin-3-one 8 and a variety of allylic alcohols, smoothly proceeded with successive Claisen rearrangement to give the corresponding 3-allyl-3-cyanomethylindolin-2-ones 15. Indolin-2-ones 15 were converted into pyrrolo[2,3-b]indoles 6 using partial hydrolysis followed by reductive cyclization with LiAlH(4). Synthesis of N-methylated pyrrolo[2,3-b]indole derivatives 23 and 26 is also described.
Kawasaki
Tomomi
T
Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan. kawasaki@my-pharm.ac.jp
Ogawa
Atsuyo
A
Terashima
Romi
R
Saheki
Toshiko
T
Ban
Naoko
N
Sekiguchi
Hiroko
H
Sakaguchi
Ken-ei
KE
Sakamoto
Masanori
M
D002384:Catalysis; D020650:Combinatorial Chemistry Techniques; D007202:Indicators and Reagents; D026121:Indole Alkaloids / Q000737:chemistry; D007211:Indoles / Q000138:chemical synthesis*; D015394:Molecular Structure; D011758:Pyrroles / Q000138:chemical synthesis*
D007202:Indicators and Reagents; D026121:Indole Alkaloids; D007211:Indoles; D011758:Pyrroles