The Knoevenagel Reaction of Aldehydes with Active Methylene Compounds Having Keto-Enol Tautomerism

DOI Web Site

Bibliographic Information

Other Title
  • ケト-エノール互変異性を有する活性メチレン化合物とアルデヒドとの Knoevenagel 反応

Search this article

Description

The Knoevenagel reactions of the various aldehydes with methyl acetoacetate and 2, 4-pentanedione as tautomers were carried out in the presence or absence of pyridine. The course of the reaction giving a β, γ-unsaturated compound was followed by the use of 1H-NMR, and the signals of the intermediates and products were assigned. It would be favorable conditions for the selective formation of the β, γ-unsaturated compounds that an active methylene compound contains great high enol populations, and that further an aldehyde possesses conjugatable groups to a double bond formed. The reaction pathway proceeds in the sequence: addition → dehydration → rearrangement. In the presence of base catalyst the dehydration reaction proceeds via the keto-type intermediate to give β, γ-unsaturated compounds. In the absence of catalyst there may also exist the route through the enol (E)-type intermediate. It is thought that the rearrangement of double bond occurs via the enol-type β, γ-unsaturated compound to give the keto-type one.

Journal

  • NIPPON KAGAKU KAISHI

    NIPPON KAGAKU KAISHI 1989 (4), 714-721, 1989-04-10

    The Chemical Society of Japan

Keywords

Details 詳細情報について

Report a problem

Back to top