838872-73-4Relevant articles and documents
Synthesis of diverse 2,3-dihydroindoles, 1,2,3,4-tetrahydroquinolines, and benzo-fused azepines by formal radical cyclization onto aromatic rings
Clive, Derrick L. J.,Peng, Jianbiao,Fletcher, Stephen P.,Ziffle, Vincent E.,Wingert, David
, p. 2330 - 2344 (2008/09/19)
(Chemical Equation Presented) 2,3-Dihydroindoles, 1,2,3,4- tetrahydroquinolines, and 2,3,4,5-tetrahydrobenzo[b]azepines are available by a process that represents formal radical cyclization onto aromatic rings. Optically pure benzo-fused heterocycles are also accessible by this method. p-Iodophenols, especially those with the phenolic oxygen protected as a MOM-ether, can be coupled with amino alcohols to produce N-aryl amino alcohols, which can be converted into the corresponding alkyl iodides in which the nitrogen is protected as a carbamate. These compounds give cross-conjugated ketones after removal of the phenolic protecting group and oxidation with PhI(OAc)2 in the presence of MeOH. The ketones undergo 5-, 6- or 7-exo-trigonal radical cyclization, and then exposure to acid, or sequential treatment with a Grignard reagent and then acid, effects rearomatization to produce the benzo-fused nitrogen heterocycles.
