Synfacts 2010(5): 0555-0555  
DOI: 10.1055/s-0029-1219643
Metal-Catalyzed Asymmetric Synthesis and Stereoselective Reactions
© Georg Thieme Verlag Stuttgart ˙ New York

Rhodium-Catalyzed Asymmetric Cycloisomerization of 1,6-Enynes

Contributor(s): Hisashi Yamamoto, Dmitry L. Usanov
T. Nishimura*, T. Kawamoto, M. Nagaosa, H. Kumamoto, T. Hayashi*
Kyoto University, Japan
Further Information

Publication History

Publication Date:
22 April 2010 (online)

Significance

1,6-Enynes can be converted into bicyclo[4.1.0]heptene derivatives via 6-endo-dig cycloisomerization catalyzed by π-acidic metals. Despite the high synthetic utility of this transformation, there have been only few asymmetric variants reported so far. In this paper the authors describe a rhodium-catalyzed cycloisomerization of oxygen- and nitrogen-bridged 1,6-enynes proceeding with high yields (71-94%) and enantio­selectivities (68-99% ee). Substituted tetrafluoro­benzobarrelene (TFB, 1) was found to be the optimum ligand showing high catalytic activity presumably due to its high π-accepting ability. It can be expected that the unique catalyst design will be suitable for other applications of transition-metal catalysis.