- Highly Enantioselective Synthesis of Indolines: Asymmetric Hydrogenation at Ambient Temperature and Pressure with Cationic Ruthenium Diamine Catalysts
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A highly enantioselective synthesis of indolines by asymmetric hydrogenation of 1H-indoles and 3H-indoles at ambient temperature and pressure, catalyzed by chiral phosphine-free cationic ruthenium complexes, has been developed. Excellent enantio- and diastereoselectivities (up to >99 % ee, >20:1 d.r.) were obtained for a wide range of indole derivatives, including unprotected 2-substituted and 2,3-disubstituted 1H-indoles, as well as 2-alkyl- and 2-aryl-substituted 3H-indoles.
- Yang, Zhusheng,Chen, Fei,He, Yanmei,Yang, Nianfa,Fan, Qing-Hua
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supporting information
p. 13863 - 13866
(2016/10/26)
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- Stereospecific Reduction of 3-Hydroxy-3H-indoles and of their Corresponding N-Oxides with NaBH4 and LiAlH4. Synthesis of True 1-Hydroxy-2,3-disubstituted Indoles. Crystal and Molecular Structure of 3-Hydroxy-2,3-diphenylindoline
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3-Hydroxy-3H-indoles (1) and their corresponding N-oxides (5) undergo stereospecific reduction at the double C=N bond giving the indoline derivatives (2) and (6) respectively, which, in acidic medium, lose water to give the 2,3-disubstituted indoles (3) and (7) whose physical and spectroscopic data are not in agreement with those reported previously.The structure of 3-hydroxy-2,3-diphenylindoline, one of the reduction products, was determined by X-ray diffraction, and it was shown that hydrogen adds at C-2 cis to the hydroxy-group on C-3. 3,3-Disubstituted-3H-indoles with two organic radicals on C-3 give a mixture of stereoisomers.
- Berti, Corrado,Greci, Lucedio,Poloni, Marino,Andreetti, Giovanni Dario,Bocelli, Gabriele,Sgarabotto, Paolo
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p. 339 - 346
(2007/10/02)
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