Title:Metal-Catalyzed Cross-Coupling Reactions using Olefins and/or Alkanes as starting materials
Reporter: Prof. Loh Teck Peng
Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences,Nanyang Technological University, Singapore
Tiem: 7 January, Thursday AM10:30
Location: 2nd Floor Seminar Hall Lu Jiaxi Building
Abtract:
Metal-catalyzed coupling reaction is one of the most useful organic transformations as it provides easy entry to the synthesis of many complex molecules.1 However, one of the most challenging problems associated with this method is the need to use halogenated substrates or/and organometallics. Therefore, many research groups have been focusing on exploring Metal-catalyzed coupling reaction through C–H bond activation.2 However, direct cross-coupling reactions using simple alkenes and/or alkanes have not been well studied.3 This is due to the difficulty in activating the C-H bonds. In this presentation, we report new metal-catalyzed coupling reactions without the need to use halogen containing starting materials.4,5 This method allows easy access to a wide variety of dienoates using simple olefins under mild reaction conditions (eq 1).6
An intramolecular version of this method using oximes leads to interesting oxacycles also was developed (eq 2).
The application of this new method for the synthesis of a key fragments of palmerolide will also be presented (refer to scheme below).
1. (a) Tsuji, J. Palladium Reagents and Catalysts: Innovations in Organic Synthesis; Wiley and Sons: New York, 1995. (b) Zeni, G.; Larock, R. C. Chem. Rev. 2006, 106, 4644-4680. (c) Stang, E. M.; White, M. C. Nature. Chem. 2009, 1, 547-551.
2. Chen, X.; Engle, K. M.; Wang, D.-H.; Yu, J.-Q. Angew. Chem. Int. Ed. 2009, 48, 5094-5115.
3. Hatamoto, Y.; Sakaguchi, S.; Ishii, Y. Org. Lett. 2004, 6, 4623-4625.
4. Zhou, H.; Xu, Y.-H.; Chung, W.-J.; Loh, T.-P. Angew. Chem. Int. Ed. 2009, 48, 5355-5337.
5. Zhou, H.; Chung, W.-J.; Xu, Y.-H.; Loh, T.-P. Chem. Commun. 2009, 3472-3474.
6. Xu, Y.-H; Lu, J.; Loh, T.-P. J. Am. Chem. Soc. 2009, 131, 1372-1373.
