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Fertig, Josef (1957) Mechanisms of some replacements at a 1-carbon atom (with special reference to esters of phosphorous). Doctoral thesis, Northern Polytechnic.
An approach to the elucidation of replacement at a 1-carbon atom has been made by studying the steric course principally with the outstanding example of 1-phenylethyl group and esters of phosphorus. The overall replacement of hydroxyl by halogen has proved difficult to follow by kinetic measurements especially when the alcoholic carbon atom is of considerable reactivity as it is in the 1-phenylethyl system. An effort has therefore been made to study in more detail than previously the sequence of reactions which occur when an alcohol is mixed with an inorganic non-metal halide such as thionyl chloride or the halides of phosphorus. This means that attention had to be given to reaction systems in which the final attachment of halogen to the 1-carbon atom was merely an incident which may or may not occur. When the 1-carbon atom is of the considerable reactivity of that in 1-phenylethanol, it is difficult to prevent the final attachment of halogen to the carbon, because the reaction sequences leading to this are difficult to control. Because hydrogen halide plays an important part in the phosphorus halide system, an attempt was made to prepare 1-phenylethyl chloroesters of phosphous by means of trimethylalkoxysilanes. With phosphorus trichloride and when the alkoxy group is of ordinary reactivity such as 1-butyloxy, chloroesters were readily obtained. With the 1-phenylethoxy silane and phosphorus trichloride the chloroester ROPCl2 was actually formed, this being a rare example of the established formation of such a compound in the inorganic non-metal halide systems. The decomposition of this chloroester could therefore be examined with respect to the formation of 1-phenylethyl chloride. Phosphorus oxychloride, however, immediately gave 1-phenylethyl chloride, and a new type of compound, trimethylsilylphosphorodichloridate, Me3SiOP(O)Cl2, this providing another example of the influence of reactivity of the l-carbon atom. Other examples of reactions in this system are described.
The formation of 1-phenylethyl chloride by reactions in alcohol-phosphorus halide and alcohol-thionyl halide systems has been studied, with particular reference to the influence of conditions and presence of a tertiary base on the rotatory power of the resulting alkyl halide and attempts have been made to correlate the result with the reaction sequences which probably occur. In particular an attempt has been made to account for the production in the phosphorus oxychloride systems, of 1-phenylethyl chloride having a high rotatory power whereas in so many systems the rotatory power tends to be low.
Evidence of control of certain reactions which occur in these systems has been obtained by mixing the reagents at a temperature of -80C and an interesting example of this effect is provided by the formation of alkyl phosphates from reactive alcohols (such as benzyl alcohol and 1-phenylethanol) by means of phosphorus oxybromide whereas alkyl halide is inevitably formed when there is less control as when the temperature is -10°.
A relevant survey of the literature has been recorded and explanations are submitted.
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