Indium(III)-catalyzed knoevenagel condensation of aldehydes and activated methylenes using acetic anhydride as a promoter

Yohei Ogiwara; Keita Takahashi; Takefumi Kitazawa; Norio Sakai

doi:10.1021/acs.joc.5b00011

Indium(III)-catalyzed knoevenagel condensation of aldehydes and activated methylenes using acetic anhydride as a promoter

J Org Chem. 2015 Mar 20;80(6):3101-10. doi: 10.1021/acs.joc.5b00011. Epub 2015 Feb 26.

Authors

Yohei Ogiwara¹, Keita Takahashi¹, Takefumi Kitazawa¹, Norio Sakai¹

Affiliation

¹ Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science (RIKADAI), Noda, Chiba 278-8510, Japan.

PMID: 25689032
DOI: 10.1021/acs.joc.5b00011

Abstract

The combination of a catalytic amount of InCl3 and acetic anhydride remarkably promotes the Knoevenagel condensation of a variety of aldehydes and activated methylene compounds. This catalytic system accommodates aromatic aldehydes containing a variety of electron-donating and -withdrawing groups, heteroaromatic aldehydes, conjugate aldehydes, and aliphatic aldehydes. Central to successfully driving the condensation series is the formation of a geminal diacetate intermediate, which was generated in situ from an aldehyde and an acid anhydride with the assistance of an indium catalyst.