The reactions and structure of αγ-substituted allyl alcohols : a study of the reactions and optical properties of ethylpropenylcarbinol and some of its derivatives
Ethylpropenylcarbinol (alpha-ethyl-gamma-methylallyl alcohol) has been resolved into its d- and l-forms by fractional crystallisation of the brucine salt of the hydrogen phthalic ester. Reduction of the optically active alcohol has provided data which revise the figures published for the specific ro...
| Main Author: | |
|---|---|
| Published: |
University of Surrey
1940
|
| Online Access: | https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.751424 |
| Summary: | Ethylpropenylcarbinol (alpha-ethyl-gamma-methylallyl alcohol) has been resolved into its d- and l-forms by fractional crystallisation of the brucine salt of the hydrogen phthalic ester. Reduction of the optically active alcohol has provided data which revise the figures published for the specific rotatory powers of ethyl n-propylcarbinol and its hydrogen phthalic ester. Parachor deteminations on substituted allyl alcohols and derivatives have indicated that the alcohols possess a cyclic configuration. The absence of association in allylie alcohols has been demonstrated by comparison of the effects of temperature on the parachors of these alcohols and of saturated alcohols which are known to be associated In comparison with that of methylpropenylcarbinol (alphagamma-di-methylallyl alcohol) the mutarotation of ethyl propenylcarbinol is regular, and the formation of optically active methylbutanylcarbinol (alpha-methyl-gamma-ethylallyl alcohol) has been shown to occur by anionetropic change. The cyclic configuration referred to above permits an explanation for the retention of asymmetry on already established principles. The chloride of ethylpropenylcarbinol has been prepared and has been shown to give a mixture of ethypropenyl carbinol and methylbutenylcarbinol on hydrolysis. These products have been identified by reduction and separation of derivatives of the resulting ethylpropyl- and methyl n-butylcarbinols by fractional crystallisation. Optically active ethyIpropenylcarbinyl chloride suffers extensive racemisation on hydrolysis. Thus there is usually separation of the chloride anion before attachment of the hydroxyl group, the liberation of a mesomeric kation during this process leading to racemisation and isomerisation. The problems arising from the data already published on alphagamma-di-methylallyl alcohol are discussed in the light of the results obtained in this work. |
|---|