Einwirkung von wäßriger Ba(OH)2‐Lösung auf die cis‐Isomeren (Ia) bzw. (IIa) liefert das Oxetan (III) (durch intramolekulare nucleophile Substitutionsreaktion) bzw. die ungesättigten Alkohole (IVa) + (IVb) (durch Eliminierungsreaktion).
SummaryThe transformations of isomeric 1,3-chloroalcohols 1-4, with cyclohexane skeleton, were studied in aqueous solution containing barium hydroxide. As regards the compounds with cis-configuration, 1 gives the oxetane 5 by intramolecular nucleophilic substitution, while 3 gives the unsaturated alcohols 7 and 8 by elimination. In the case of the trans-isomers 2 and 4, fragmentation reactions occur in competition with elimination. The main reaction kinetic parameters of the transformations of the four compounds were determined.We earlier reported results obtained during investigations of the reactions of aliphatic 1,3-chloroalcohols with alkali [l] [2]. Depending on the structure of the chloroalcohol, four reaction directions were observed, which could also occur in parallel with one another. These were: the formation of oxetanes by intramolecular nucleophilic substitution; the formation of unsaturated alcohols by elimination; the formation of diols by nucleophilic substitution; and fragmentation reactions accompanied by the formation of olefins and 0x0 compounds. The significance of research into this topic is demonstrated by a number of important results [3-71. Grob ef al.[8] [9] have dealt in detail with the conditions for the four possible reactions to proceed simultaneously, with the conditions for one or other reaction path to become predominant, and in particular with the theory of the fragmentation reactions. In our work we selected the four cyclohexane skeleton 1,3-chloroalcohol isomers 1-4 (see Scheme 1 ) as model compounds, in order to be able to obtain further data on the steric and stereoelectronic conditions relating to the individual reaction directions, and especially the fragmentation reactions.Results. -On the basis of 'H-NMR. examinations [lo], the configurations and conformations of the isomers 1-4 may be given as follows:In the case of the trans-isomers 2 and 4, the functional groups are equatorial, and the ring is free from conformational motion. In the cis-isomers 1 and 3, the hetereoatom is axial, and the chair conformation is distorted to a certain extent.
Zur i Synthese der 2,3‐Dialkyl‐oxetane (IV) werden die Diole (I) in die Chlorhydrin‐O‐ acetate (II) übergeführt; diese O‐Acetate werden direkt oder nach ihrer Überführung g in die Chlorhydrine (III) cyclisiert.
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