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

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 (2R, 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).