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Wilson, Barbara M. (1951) Interaction of neopentyl alcohol and derivatives with certain inorganic halides. Doctoral thesis, Northern Polytechnic.
neoPentyl alcohol reacts with non-metallic inorganic halides such as thionyl and phosphorus halides just as readily as does for example n-butyl alcohol, and gives rise to a series of esters of the types RO3OC1, ROPC12, ROSiCl3. In the presence of pyridine the formation of esters of the types (RO)2SO, (RO)3P, (RO)4Si, is very rapid even at -10°. All these reactions involve the replacement of the alcoholic hydrogen atom, and from a consideration of the experimental conditions which prevailed, and from a consideration of the stability of the esters, it is clear that the alcoholic carbon—oxygen bond is difficult to break. It may be inferred that the neopentyl skeleton does not readily re-arrange, on the contrary; but when one tries to force the rupture of the carbon—oxygen bond, then the steric hindrance which opposes the rupture is relieved by a rearrangement which results in the formation of a tertiary alkyl halide.
Methyl neopentyl alcohol (methyltert.-butylcarbinol) is very rapid even at -10° formed the aforementioned esters with the same readiness, but these compounds were not as stable in this example, presumably because of the secondary alcoholic structure rather than any special contribution by the tert-butyl structure. The carbon—oxygen bond is more readily broken, and again it appears that it is not the tendency of the neopentyl structure to rearrange which is dominating the situation, but rather that rearrangement is able to relieve the strain when the carbon—oxygen bond is challenged with sufficient determination. Optically active methyl neo-pentyl alcohol was also used in the hope that from all the reaction sequences that were examined there would be found at of least one which would lead to the satisfactory preparation of the optically active alkyl halide. Unfortunately this preparation was not achieved.
In the main the corresponding esters of methylisopropyl-carbinol were also easily prepared, and these were found to be of a similar stability as the methyl neopentyl analogues. When the carbon-oxygen bond was challenged with sufficient force rearrangement occurred.
The experimental results are discussed in terms of end-on and broadside approaches of the reacting molecules.
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