A-Phenylethyl chloride

Under comparable conditions the corresponding alkylations of phenylacetic acid with a-phenylethyl chloride and benzhydryl chloride have been effected to form o ,/3-diphenylbutyric acid and a ,/3,/3-triphenylpropionic acid in yields of 74% and 51%, respectively. ... 

The method described is successfully used for the alkylation and aralkylation of ethyl and /-butyl phenylacetate.3 The alkylation of ethyl phenylacetate with methyl iodide, M-butyl bromide, benzyl chloride, and a-phenylethyl chloride affords the corresponding pure monoalkylation products in 69%, 91%, 85%, and 70% (erythro isomer) yields, respectively. The alkylation of /-butyl phenylacetate with methyl iodide, M-butyl bromide, a-phenylethyl chloride, and /3-phenylethyl bromide gives the corresponding pure monoalkylated products in 83%, 86%, 72-73%, and 76% yields, respectively. 

Allyl chloride and a-phenylethyl chloride are reduced by Cr(II) sulphate in aqueous dimethyl formamide (DMF) in a simple second-order process. At 29.7... 

With a-phenylethyl chloride the tendency towards ionization is greater, and it is only in certain solvents that a second order, con-118 . D. Hughes, C. K. Ingold, and S. Masterman, /. Chetn. Soc., 1937,1196. 

In a few cases, SnI reactions have been found to proceed with partial retention (20 to 50%) of configuration. Ion pairs have been invoked to explain some of these.51 For example, it has been proposed that the phenolysis of optically active a-phenylethyl chloride, in which the ether of net retained configuration is obtained, involves a four-center mechanism ... 

The ethanolysis of benzhydryl chloride (16) is 270 times more rapid than that of a-phenylethyl chloride (17) (Streitwieser, 1956). Also... 

In relation to the six-membered transition state proposed for the pyrolysis of a-chloro-o-xylene which gives benzocyclobutene and HC1, the gas-phase elimination of a-phenylethyl chloride was carried out in the presence of in order to see whether... 

Racemization in an S l reaction arises, then, from the loss of configuration in the intermediate carbonium ion. In some cases racemization may be almost complete hydrolysis of a-phenylethyl chloride, for example, proceeds with 87% racemization and 13% inversion ... 

Although the Williamson synthesis usually proceeds by Sn2, halides are known whose rate of etherification is independent of the concentration of alkoxide ion in a solution of the corresponding alcohol. Tri-phenylmethyl chloride and a-phenylethyl chloride are examples (p. 83). 

Optically active comoounds have been employed to investigate the nature of intermediates in model cationic reactions involving alkylaluminum compounds. Alberola (IS) in 1969 investigated the stereochemistry of alkylation using (—)a-phenylethyl chloride with Et3Al in p-xylene. The formation of predominantly racemic product was taken as evidence for carbenium ion-counter anion intermediates. Kennedy, Desai and Sivaram (7) modified this scheme to avoid undesirable side reactions by using a nonreactive solvent such as ethyl chloride at — 65° C. Analysis of the products again confirmed the fact that the stereochemical consequence of alkylation is predominant racemization which is consistent with the hypothesis that the intermediate involved in alkylation is a loose carbenium ion-counteranion pair. 

With sodamide in liquid ammonia, dimeric halides (20b) were isolated in good yield. Experiments with optically active a-phenylethyl chloride indicated that the displacement reaction (20b) proceeds with Walden inversion. Clearly, the bimolecular displacement mechanism operates in the benzyl and benzhydryl series at low temperatures. 

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