Dimetallation of ortho-Cresol

Functionalization reactions with butyl bromide and trimethylchlorosilane (bis-silylation). 

Apparatus p. 24, Fig. 1 11 for the addition of the f-BuOK the dropping funnel is temporarily replaced by a powder funnel. 

To a solution of 0.21 mol of BuLi in 140 ml of hexane is added 0.21 mol (24.3 g) of TMEDA. The solution is cooled to — 50 °C and a mixture of 0.1 mol (10.8 g) of o-cresol and 40 ml of hexane is added over a few min with cooling below — 20 °C. Subsequently, finely powdered (under a dry atmosphere) t-BuOK (0.11 mol, 12.4 g) is added over 5 min while keeping the temperature between —25 and — 35 °C. The mixture is gently stirred for 3h at —20 to — 25 °C. Most of the suspended material dissolves within 15 min and a turbid, yellow solution is formed. After the 3-h period the cooling bath is removed and the temperature allowed to rise to 

4 Metallation of o- and /i-Tolunitrile with Alkali Amides in Liquid Ammonia and Alkali Diisopropylamide in THF-Hexane Mixtures 

Apparatus For the reactions in liquid ammonia a 1-1 round-bottomed, threenecked flask, equipped with a dropping funnel, a mechanical stirrer, and a gas-outlet for the reaction in THF-hexane mixtures see p. 24, Fig. 1 500 ml. 

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