On February 20, 2006, Kuwano, Ryoichi; Kashiwabara, Manabu; Sato, Koji; Ito, Takashi; Kaneda, Kohei; Ito, Yoshihiko published an article.SDS of cas: 79815-20-6 The title of the article was Catalytic asymmetric hydrogenation of indoles using a rhodium complex with a chiral bisphosphine ligand PhTRAP. And the article contained the following:
Nonracemic N-substituted indolines are prepared by enantioselective hydrogenation of N-protected indoles in the presence of a rhodium catalyst generated in situ from bis(norbornadiene)rhodium(I) hexafluoroantimonate and nonracemic bis(diphenylphosphinoethyl)biferrocenes with cesium carbonate as base in isopropanol. Other rhodium precursors such as (μ4-1,5-cyclooctadiene)rhodium (I) acetylacetonate and bases such as triethylamine are effective for the enantioselective hydrogenation of 1-substituted indolines; use of solvents other than isopropanol gives indolines in decreased yields and enantioselectivities or (in the case of methanol) no product. Hydrogenation of 1-acetylindoles with iso-Bu, methoxycarbonyl, Ph, Me or Bu groups at the 2-positions gives the corresponding chiral indolines in 45-98% yields and in 79-95% ee; changing the acetyl group to a tert-butoxycarbonyl or a tosyl group yields indolines in 77-78% ee, while 2-cyclohexyl-1-acetylindole gives the corresponding indoline in 27% yield and 19% ee. Hydrogenation of 3-substituted N-tosylindoles yields 3-substituted 1-tosylindoles; changing the tosyl group to a tert-butoxycarbonyl group decreases enantioselectivity and yield drastically, while replacement of the tosyl group with either a mesyl or a triflyl group gives indoline products with decreased yields and similar enantioselectivities. Me 1-tosyl-3-indolepropanoate, tert-Bu 1-tosyl-3-indoleacetate, and 3-acetyl-1-tosylindole are hydrogenated to indolines in diminished yields and/or selectivities. The experimental process involved the reaction of H-Idc-OH(cas: 79815-20-6).SDS of cas: 79815-20-6
The Article related to indoline enantioselective preparation, stereoselective hydrogenation indole rhodium phenylphosphinoethylbiferrocene catalyst, effect base solvent stereoselective hydrogenation indole rhodium phenylphosphinoethylbiferrocene, catalytic asym hydrogenation indole rhodium complex bisphosphine phtrap and other aspects.SDS of cas: 79815-20-6
Referemce:
Indole alkaloid derivatives as building blocks of natural products from Bacillus thuringiensis and Bacillus velezensis and their antibacterial and antifungal activity study,
Preparation of Indole Containing Building Blocks for the Regiospecific Construction of Indole Appended Pyrazoles and Pyrroles