Sodium hydride (60% dispersion in mineral oil),
Chloromethyl methyl ether (Aldrich),
m-Cresol,
Dimethylformamide (distilled from magnesium sulfate).
Ether
Pentane

Sodium hydride (5.54 g, 0.14 mol) was washed with dry pentane (3 x 50 mL). The residue was suspended in ether (40 mL) and dimethylformamide (10 mL) was added. The grey suspension was cooled to 0 ^oC and m-cresol (4.84 mL, 0.046 mol) was added dropwise and stirred for 30 minutes until gas evolution had ceased. Chloromethyl methyl ether (3.5 mL, 0.046 mol) was then added and the mixture allowed to stir at room temperature for 3 hours. Excess sodium hydride was destroyed by the addition of water (30 mL). The reaction was diluted with ether (20 mL) and washed with water (3 x 50 mL), brine (2 x 50 mL), separated, dried (MgSO₄) and filtered. The solvent was removed from the filtrate in vacuo and the crude product purified by flash column chromatography (5% Ether / Petrol) to yield the product as a clear oil (6.49 g, 43 mmol, 93%).

We have performed this reaction 5 times on scales of around 5 g of m-cresol. The reaction is pretty straightforward. Care should be taken when handling the very carcinogenic chloromethyl methyl ether and when destroying excess sodium hydride.

¹H NMR (300 MHz, CDCl₃) 7.23 (1H, t), 6.90 (1H, s), 6.87 (1H, d) 6.85 (1H, d) 5.20 (2H, s) 3.52 (3H, s) 2.39 (3H, s)

Ronald, R. C.; Winkle, M. R.; Tetrahedron, 1983, 39, 2031.