Functionalization of Benzylic C(sp3)[BOND]H Bonds of Heteroaryl Aldehydes through N-Heterocyclic Carbene Organocatalysis

Authors

  • Xingkuan Chen,

    1. Division of Chemistry & Biological Chemistry, School of Physical & Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore)
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  • Prof. Dr. Song Yang,

    1. State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025 (China)
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  • Prof. Dr. Bao-An Song,

    Corresponding author
    1. State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025 (China)
    • Bao-An Song, State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025 (China)

      Yonggui Robin Chi, Division of Chemistry & Biological Chemistry, School of Physical & Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore)

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  • Prof. Dr. Yonggui Robin Chi

    Corresponding author
    1. Division of Chemistry & Biological Chemistry, School of Physical & Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore)
    • Bao-An Song, State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025 (China)

      Yonggui Robin Chi, Division of Chemistry & Biological Chemistry, School of Physical & Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore)

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  • We thank the Singapore National Research Foundation (NRF), Singapore Economic Development Board (EDB), GlaxoSmithKline (GSK) and Nanyang Technological University (NTU) for generous financial support, and Drs. Y. Li and R. Ganguly (NTU) for assistance with X-ray crystallography. S.Y. and B.-A.S. acknowledge financial support from the National Key program for Basic Research (2010CB 126105) and the National Natural Science Foundation of China (21132003).

Abstract

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Aryl aldehyde activation: Oxidative activation of 2-methylindole-3-carboxaldehyde (I) through N-heterocyclic carbene (NHC) organocatalysis generates heterocyclic ortho-quinodimethane (II) as a key intermediate. This intermediate then undergoes formal [4+2] cycloaddition with trifluoromethyl ketones or isatins to form polycyclic lactones containing a quaternary carbon center.

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