[CH3:1][Si:2]([CH3:15])([CH3:14])[C:3]#CB1C2CCCC1CCC2.[CH3:16][C:17](=[O:24])[CH2:18][CH2:19][CH2:20][CH2:21][CH2:22][CH3:23].CO.[CH2:27](CN)O>O1CCCC1.C(OCC)C>[CH3:1][Si:2]([CH3:15])([CH3:14])[C:3]#[C:16][C:17]([CH3:27])([OH:24])[CH2:18][CH2:19][CH2:20][CH2:21][CH2:22][CH3:23]Dissolve B-(2-(trimethylsilyl)ethynyl)-9-borabicyclo[3.3.1]nonane.tetrahydrofuran complex (2.63 g, 9 mmol) in tetrahydrofuran (30 mL) and add 2- octanone (1.41 mL), 9 mmol). Stir at 65° C. for 48 hours. Cool to room temperature and remove the solvent under a positive nitrogen pressure to give a yellow solid. Add ethyl ether (30 mL) and methanol (365 μL, 9 mmol). Cool to 0° C. and add, by dropwise addition, ethanolamine (543 μL, 9 mmol). Stir overnight, centrifuge the reaction mixture and separate the clear supernatnat liquid. Wash the precipitate with pentane (2×10 mL) and combine the organic phases. Wash with water (2×25 mL) and dry (MgSO4). Evaporate the solvent in vacuo and purify by silica gel chromatography (20:5:1/hexane, chloroform, methanol) to give the title compound as a pale yellow liquid (1.45 g, 71%).
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