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Synfacts 2010(9): 1039-1039  
DOI: 10.1055/s-0030-1257949
Metal-Catalyzed Asymmetric Synthesis and Stereoselective Reactions
© Georg Thieme Verlag Stuttgart ˙ New York

Asymmetric Hydrogenation of Unprotected Indoles

Contributor(s): Mark Lautens, Stephen G. Newman
D.-S. Wang, Q.-A. Chen, W. Li, C.-B. Yu, Y.-G. Zhou*, X. Zhang*
Dalian Institute of Chemical Physics, P. R. of China; The State University of New Jersey, Piscataway, USA
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Publication History

Publication Date:
23 August 2010 (online)

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Significance

Chiral indolines are often found in natural products and other biologically active molecules. Many groups have explored asymmetric hydrogenation of indoles as a method to access this family. While success has been achieved with reduction of protected indoles, the use of unprotected substrates would provide a more direct route. The authors present the first example of a general, enantioselective hydrogenation of unprotected indoles to synthesize chiral indolines. Key to this finding was the use of a palladium catalyst under a high pressure of hydrogen gas in the presence of one equivalent of l-(-)-camphorsulfonic acid (l-CSA).