Chloromethyl ethyl ether (as received),
THF (distilled from sodium/benzophenone),
glyoxal-bis-(2,6-diisopropylphenyl)imine Page 28,
Water.

To a solution of chloromethyl ethyl ether (1.82; 18.3 mmol) in THF (3 cm³) (in a 100 cm³ round-bottomed flask)was added glyoxal-bis-(2,6-diisopropylphenyl)imine (6.89 g; 18.3 mmol) in THF (40 cm³), and 2 drops of water. The flask was degassed by passing nitrogen into it for a short period of time, and sealed with a rubber septum. The mixture was stirred at 40^oC for 16 hours, then cooled and filtered, and dried under vacuum. The product was obtained as a pink-white solid (1.71 g; 35%), m.p. 280 ^oC (dec.), lit. (Arduengo) >255 ^oC.

The procedure succeeded (at the second attempt) despite the reaction mixture going a very dark colour quickly. An indication as to whether the reaction is working is that the product should appear as a powder after about an hour. The whole method does seem a bit unusual, especially considering that the synthesis of a closely related analogue (2,4,6-trimethylphenyl analogue) was reported in the same paper in the presence of molecular sieves, rather than with added water. For related pages regarding the N-heterocyclic carbene precatalysts, see Page 28,Page 30,Page 31,Page 34

¹H nmr, 1.25 (12H, d, J = 6.8 Hz), 1.29 (12H, d, J = 6.6 Hz), 2.45 (4H, septet, J = 6.9 Hz), 7.36 (4H, d, J = 7.9 Hz), 7.58 (2H, t, J = 7.8 Hz), 8.17 (2H, s), 10.06 (1H, s)

A. J. Arduengo, R. Krafczyk, R. Schmutzler, H. A. Craig, J. R. Goerlich, M. J. Marshall, M. Unverzagt, Tetrahedron, 1999, 55, 14523.