Benzyl-o-tolyl rearrangement

Treatment of benzylmagnesium chloride with formaldehyde leads, not to phenethyl alcohol, but to 2-methylbenzyl alcohol 106 

Smith and Spillane107 describe this reaction as follows  

Paraformaldehyde (165 g dried for several days over phosphoric oxide in a vacuum) is added to a filtered ethereal solution of benzylmagnesium chloride (from 3.4 moles of benzyl chloride). The mixture is boiled, with stirring, for 18 h, then poured on ice and acidified with dilute sulfuric acid. The organic layer is washed successively with water, 5 % sodium carbonate solution and water. The aqueous phases are extracted with ether, and these extracts are washed as before. Fractionation of the united ethereal layers through a filled column afford 2-methyl-benzyl alcohol (248-263 g, 59-63%), b.p. 106-109°/12 mm. 

The alcohol thus obtained can be converted into its chloride and subjected to similar reaction. By three successive such rearrangements, Reichstein and his co-workers108 obtained 2,3,4-trimethylbenzyl alcohol, but the yields in the later stages were unsatisfactory. 

Tiffeneau and R. Delange, Compt. rend. Hebd. Seances Acad. Sci., 137, 573 (1903). 

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