Catalytic Effect of Zinc Chloride on the Claisen Rearrangement of Allyl [o(or p)-Substituted Phenyl] Ethers

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  • HAYASHI Takatoshi
    Department of Chemistry, Faculty of Science and Engineering, Ritsumeikan University
  • GOTO Masanobu
    Department of Chemistry, Faculty of Science and Engineering, Ritsumeikan University

Bibliographic Information

Other Title
  • Claisen転位反応におよぼす塩化亜鉛の影響
  • Ｃｌａｉｓｅｎ転位反応　ＩＩ　　Ｃｌａｉｓｅｎ転位反応に及ぼす塩化亜鉛の影響

Description

The Claisen rearrangement of allyl phenyl ethers that have a number of ortho or para substituents varying from electron withdrawing to electron releasing groups was found to be catalyzed by zinc chloride. In the case of p-substituted compounds, the order of the magnitude of the catalytic effect of zinc chloride on the conversion was observed as follows.<BR>CH3O>CH3>H>t-Bu>Cl>CHO≅/≈COCH3>NO2<BR>Namely, the catalytic effect decreased with increasing the electronegativity of the substituent. In the case of o-substituted compounds, the catalytic effect of zinc chloride was remarkably different from that of para isomers, and the order was as follows.<BR>CH3O>COOCH3>COCH3>CH3, CHO>H>Cl>NO2>t-Bu<BR>Particularly, the catalytic effect to the compounds having ortho carbonyl group was larger than that of para isomers. From the data of IR and others, it was considered that the cata- lytic action of zinc chloride on the Claisen rearrangement was occurred by coordination of zinc chloride to the ether oxygen at the transition state.<BR>Consequently, it was supposed that the magnitude of the catalytic effect of zinc chloride to the conversion was governed by the intensity of coordination of zinc chloride at the ether oxygen, and that the intensity of coordination was controlled by inductive effect, steric hindrance and chelating effect of ortho substituent.

Journal

  • NIPPON KAGAKU KAISHI

    NIPPON KAGAKU KAISHI 1978 (7), 1007-1012, 1978-07-10

    The Chemical Society of Japan

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