110659-07-9Relevant articles and documents
Catalytic asymmetric hydrogenation of indoles using a rhodium complex with a chiral bisphosphine ligand PhTRAP
Kuwano, Ryoichi,Kashiwabara, Manabu,Sato, Koji,Ito, Takashi,Kaneda, Kohei,Ito, Yoshihiko
, p. 521 - 535 (2007/10/03)
Highly enantioselective hydrogenation of N-protected indoles was successfully developed by use of the rhodium catalyst generated in situ from [Rh(nbd)2]SbF6 and the chiral bisphosphine PhTRAP, which can form a trans-chelate complex with a transition metal atom. The PhTRAP-rhodium catalyst required a base (e.g., Cs2CO3) for the achievement of high enantioselectivity. Various 2-substituted N-acetylindoles were converted into the corresponding chiral indolines with up to 95% ee. The hydrogenations of 3-substituted N-tosylindoles yielded indolines possessing a stereogenic center at the 3-position with high enantiomeric excesses (up to 98% ee).
Synthesis of methyl 5- and 6-nitroindole-2-carboxylates by nitration of indoline-2-carboxylic acid
Lavrenov, Sergei N.,Lakatosh, Sergei A.,Lysenkova, Ludmila N.,Korolev, Alexander M.,Preobrazhenskaya, Maria N.
, p. 320 - 322 (2007/10/03)
Indoline-2-carboxylic acid was transformed into 6-nitroindoline-2-carboxylic acid, the methyl ester of which was easily dehydrogenated by DDQ to methyl 6-nitroindole-2-carboxylate (total yield: 67%). Methyl 5-nitroindole-2-carboxylate was obtained by the nitration of methyl 1-acetylindoline-2-carboxylate acid followed by dehydrogenation with MnO2 in toluene in 40% total yield.
