Reverse aromatic cope rearrangement of 2-allyl-3-alkylideneindolines driven by olefination of 2-allylindolin-3-ones: synthesis of alpha-allyl-3-indole acetate derivatives.
The reverse aromatic Cope rearrangement of 2-allyl-3-alkylideneindolines obtained by Horner-Wadsworth-Emmons olefination of 2-allylindolin-3-ones was performed. When 2-allylindolin-3-ones were treated with phosphonium ylides in refluxing toluene, domino Wittig reaction and reverse aromatic Cope rearrangement took place to give alpha-allyl-3-indole acetate derivatives in good yields. The aromatization as a new driving force in the Cope rearrangement is preferable to the conjugation with the carbonyl and cyano groups and also to the alkyl substitution pattern, which are well-known driving forces.
Kawasaki
T
T
Meiji Pharmaceutical University, 2-522-1, Noshio, Kiyose, Tokyo 204-8688, Japan. kawasaki@my-pharm.ac.jp
Nonaka
Y
Y
Watanabe
K
K
Ogawa
A
A
Higuchi
K
K
Terashima
R
R
Masuda
K
K
Sakamoto
M
M