Chinese Journal of Catalysis ›› 2020, Vol. 41 ›› Issue (6): 970-976.DOI: 10.1016/S1872-2067(19)63515-1

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Selective C3-alkenylation of oxindole with aldehydes using heterogeneous CeO2 catalyst

Md. Nurnobi Rasheda, Abeda Sultana Touchya, Chandan Chaudharib, Jaewan Jeona, S. M. A. Hakim Siddikia, Takashi Toyaoa,c, Ken-ichi Shimizua,c   

  1. a Institute for Catalysis, Hokkaido University, N-21, W-10, Sapporo 001-0021, Japan;
    b Department of Chemical Systems Engineering, Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan;
    c Elements Strategy Initiative for Catalysts and Batteries, Kyoto University, Katsura, Kyoto 615-8520, Japan
  • Received:2019-07-30 Revised:2019-09-18 Online:2020-06-18 Published:2020-01-21
  • Contact: S1872-2067(19)63515-1
  • Supported by:
    This study was supported financially by a series of JSPS KAKENHI grants:17H01341, 18K14051, 18K14057, and 19K05556 from the Japan Society for the Promotion of Science (JSPS) and by the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT) within the projects "Integrated Research Consortium on Chemical Sciences (IRCCS)" and "Elements Strategy Initiative to Form Core Research Center", as well as by the JST-CREST project JPMJCR17J3.

Abstract: We report herein that a commercially available CeO2 is an active and reusable catalyst for the C3-selective alkenylation of oxindole with aldehydes under solvent-free conditions. This catalytic method is generally applicable to different aromatic and aliphatic aldehydes, giving 3-alkyledene-oxindoles in high yields (87%-99%) and high stereoselectivities (79%-93% to E-isomers). This is the first example of the catalytic synthesis of 3-alkenyl-oxindoles from oxindole and various aliphatic aldehydes. The Lewis acid-base interaction between Lewis acid sites on CeO2 and benzaldehyde was studied by in situ IR. The structure-activity relationship study using CeO2 catalysts with different sizes suggests that defect-free CeO2 surface is the active site for this reaction.

Key words: Oxindole, Aldehyde, Aldol condensation, C3-alkenylation, CeO2 catalyst