摘要：

A. Preparation of 2-Pyridyltriolborate. A three-necked, 500-mL round-bottomed flask is fitted with a mechanical stirrer (PTFE blade, 15 x 46 mm), a Claisen adapter with an internal thermometer and pressure-equalizing addition funnel, and a reflux condenser to which a nitrogen inlet and an oil bubbler are attached, and the apparatus is flushed with nitrogen (Note 1). The flask is charged with 300 mL of THF (Note 2) and 2-bromopyridine (1) (9.7 mL, 100 mmol) (Note 3). The mixture is cooled to -78 °C and 40.0 mL of n-butyllithium solution (2.5 M in hexane, 100 mmol) (Note 4) is added dropwise at a rate of 1 mL/min using the addition funnel (Note 5). The mixture is stirred for 45 min while maintaining the internal temperature at -78 °C. Triisopropylborate (23 mL, 100 mmol) (Note 3) is then added using the additional funnel (2 mL/min) (Note 6). The mixture is stirred for 1 h at -78 °C and then is allowed to warm to room temperature. The Claisen adapter is removed, and 1,1,1-tris(hydroxymethyl)ethane (12 g, 100 mmol) (Note 7) is added in one portion. The neck is tightly sealed with a glass stopper. The mixture is refluxed for 0.5 h and is cooled to room temperature.

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