Kinetic Studies on Solvolysis. VII. On the Kinetic Resolution at the First Stage of the SNl-type Solvolysis of α-Phenethyl Chloride in Optically Active Carboxylic Acid Solvents

• Kunio Okamoto

  Department of Fuel Chemistry Faculty of Engineering Kyoto University

• Ken-ichi Takeuchi

  Department of Fuel Chemistry Faculty of Engineering Kyoto University

• Haruo Shingu

  Department of Fuel Chemistry Faculty of Engineering Kyoto University

抄録

1) In SN2 displacement reactions of (±)-α-phenethyl chloride with triethylammonium (+)-α-methyl camphorate and with triethylammonium (−)-pinonate in dioxane, α-phenethyl chloride of 0.08% of optical purity (l-configuration) and of 0.15% of optical purity (l-configuration) were recovered at the stage of about 5% conversion, respectively. 2) In SN1-type solvolysis of (±)-α-phenethyl chloride with anilinium (+)-α-methyl camphorate and (−)-pinonate in acetonitrile, the recovered α-phenethyl chlorides showed no perceptible optical activity on the half way for each of the reactions. From this, the possibility of the induced resolution caused at the first stage by kinetic resolution at the second stage of the SN1-type solvolysis was eliminated. 3) In SN1-type solvolysis of (±)-α-phenethyl chloride in (+)-α-methyl hydrogen camphorate and in (−)-pinonate, about half of the chloride was converted to the ester at the similar reaction conditions (temperature and time) to the SN2 displacement reactions carried out in dioxane. The recovered chloride in the reaction in hydrogen camphorate showed optical purity of 0.54∼0.58% (l-configuration). In pinonic acids with various optical activities the recovered chlorides possessed optical purity of 0.13∼0.27% (d-configuration). 4) In comparing the configurations and optical purities in SN1- and SN2-conditions, it is concluded that optically active solvent molecules, like (+)-α-methyl hydrogen camphorate and (−)-pinonic acid, can cause kinetic resolution in the first ionization stage of the SN1 type solvolysis and therefore they obviously play a rôle as a kind of reactant molecule which controls the steric course of the solvation reaction in the first stage of this solvolysis. 5) In the SN1-type solvolysis of optically active α-phenethyl chloride in presence of triethylamine in (+)-α-methyl hydrogen camphorate, optically active β-(α-phenethyl)-α-methyl camphorate gave optically active α-phenethyl alcohol of 37% inversion, 63% racemization of configuration. From this it was concluded that SN2-like spatial orientation predominates at the second stage of this solvolysis. 6) For each of the resolution results of α-phenethyl chloride under SN1- and SN2-conditions, the relationship between the configuration of the resolved alcohol and the resolution controlling stage was predicted on the basis of the observed inversion at the second stage of the solvolysis. The configurations observed for the α-phenethyl alcohols were found to be consistent with the predictions.

収録刊行物

• Bulletin of the Chemical Society of Japan

  Bulletin of the Chemical Society of Japan 34 (8), 1137-1143, 1961-08-01

  Oxford University Press (OUP)

キーワード

• General Chemistry

詳細情報

• CRID: 1360846644027882624
• NII論文ID: 130001960921
• DOI: 10.1246/bcsj.34.1137
• ISSN: 13480634
• ISSN: 00092673
• Web Site: https://academic.oup.com/bcsj/article-pdf/34/8/1137/56185589/bcsj.34.1137.pdf
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