Über die Chemie des Vitamins E. 1. Mitteilung. Die Umkehrung der Konfiguration am Kohlenstoffatom 2 von natürlichem (2 <i>R</i>, 4′ <i>R</i>, 8′ <i>R</i>)‐α‐Tocopherol

Abstract

Abstract (2 S , 4′ R , 8′ R )‐α‐Tocopherol with unnatural configuration at C‐2 is prepared by oxidation of natural, so called d ‐α‐tocopherol (I), which has the (2 R , 4′ R , 8′ R )‐configuration, to α‐tocopherylquinone (II), followed by recyclization of the corresponding α‐tocopherylhydroquinone (III). Experiments showed that the configuration of carbon atom 2 of natural α‐tocopherol is retained during the ferric chloride oxidation (I →II) and is predominantly inverted by zinc chloride cyclization of α‐tocopherylhydroquinone (III).