2-Methoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane → HCID 178494314, compound

Participants

Reaction Conditions

Reaction Steps

A solution of 1-(trans-4-{[tert-butyl(dimethyl)silyl]oxy}cyclohexyl)-4-iodo-3-methoxy-1H-pyrazole (0.0500 g, 0.114 mmol) in anhydrous degassed THF (2.0 mL) was cooled to −10° C. and dropwise charged with 1.30 M of isopropylmagnesium chloride in THF (0.352 mL, 0.458 mmol) over a 5 min period under an atmosphere of Argon. The reaction was maintained at −10° C. for 40 min then charged with 2-methoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (0.0939 mL, 0.573 mmol) and stirred for an additional 1 h at 0° C. The reaction mixture was quenched with sat NH4Cl (2.0 mL) and partitioned between EtOAc and H2O. The aqueous was re-extracted with EtOAc (3×) and the combined organic fractions were washed with brine (1×), dried over Na2SO4, filtered and concentrated in vacuo resulting in a crude yellow oil. The crude was purified by chromatography on silica gel [ISCO Combiflash, 4 g gold cartridge, eluting with 100% heptane→30% EtOAc in heptane] resulting in the title compound as a white waxy solid. 1H NMR (400 MHz, CD3OD): δ=−0.02-0.02 (m, 6H), 0.79-0.84 (m, 9H), 1.19 (s, 12H), 1.32-1.44 (m, 2H), 1.66-1.78 (m, 2H), 1.85-1.92 (m, 2H), 1.94-2.02 (m, 2H), 3.60-3.69 (m, 1H), 3.76-3.79 (m, 3H), 3.86 (tt, J=3.8, 12 Hz, 1H), 7.50 (s, 1H). MS (ES+): m/z 436.27, 437.26, 438.29 [MH+]. HPLC: tR=4.05 min (vvnonpolar—5 min, ZQ3).

Provenance & Evidence