2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane → 2-(3-Pyrrolidin-1-ylpropoxy)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine

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Reaction Steps

n-Butyllithium (5.68 mL, 14.20 mmol) was added dropwise to a mixture of 5-bromo-2-(3-pyrrolidin-1-ylpropoxy)pyridine (2.7 g, 9.47 mmol) and 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2.64 g, 14.20 mmol) in THF (20 mL) at −78° C. over a period of 10 minutes under an inert atmosphere. The resulting mixture was allowed to warm to ambient temperature and stirred for 12 h. The reaction mixture was quenched by the addition of a sat. aqueous solution of ammonium chloride, extracted with EtOAc (2×50 mL) and the organic layer dried over Na2SO4, filtered and evaporated to afford the desired material (3.10 g, 99%) as a yellow oil. The product was used in the next step directly without further purification, NMR Spectrum: 1H NMR (400 MHz, CDCl3) δ 1.26-1.41 (12H, m), 1.77-1.80 (4H, m), 1.95-2.04 (2H, m), 2.50-2.58 (4H, m), 2.62 (2H, t), 4.37 (2H, t), 6.69 (1H, d), 7.91 (1H, d), 8.52 (1H, s). Mass Spectrum: m/z (ES+)[M+H]+=251.

Provenance & Evidence