Synthesis of 2-substituted indoles and indolines via Suzuki-Miyaura coupling/5-endo-trig cyclization strategies.
New strategies for the synthesis of 2-substituted indoles and indolines using acyclic, imide-derived enol phosphates, which were readily prepared from o-haloanilides, have been developed based on Suzuki-Miyaura coupling-cyclization sequences. A highly chemoselective cross-coupling of imide-derived enol phosphates with boron nucleophiles under Suzuki-Miyaura conditions allowed for the efficient preparation of various N-(o-halophenyl)enecarbamates that served as useful precursors for subsequent 5-endo-trig Heck or 5-endo-trig aryl radical cyclizations to furnish 2-substituted indoles or indolines, respectively. Furthermore, a one-pot Suzuki-Miyaura coupling-cyclization cascade starting from enol phosphates has been developed, which was successfully applied to the efficient synthesis of an indol-2-yl-1H-quinolin-2-one KDR inhibitor.
Fuwa
Haruhiko
H
Laboratory of Biostructural Chemistry, Graduate School of Life Sciences, Tohoku University, 1-1 Tsutsumidori-amamiya, Aoba-ku, Sendai 981-8555, Japan. hfuwa@bios.tohoku.ac.jp
Sasaki
Makoto
M
D003500:Cyclization; D007094:Imides / Q000737:chemistry; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D010755:Organophosphates / Q000737:chemistry; D013237:Stereoisomerism
D007094:Imides; D007211:Indoles; D010755:Organophosphates; C057812:indoline