(2-Methylpropyl)boronic acid → 4,4,5,5-Tetramethyl-2-(2-methylpropyl)-1,3,2-dioxaborolane

Participants

Reaction Steps

A solution of 50.13 g (0.494 mol) of 2-methylpropylboronic acid in 300 mL of ether, prepared by a procedure substantially similar to the foregoing, was contacted with 112.63 g (0.494 mol) of pinacol hexahydrate and stirred for 24 hours. At the end of this period, the resulting reaction mixture was diluted with 500 mL of hexane. A top layer formed which was separated from the rest of the mixture and contacted with 18 mL of water. After stirring for 15 minutes, 9.52 g of a solid separated, which was removed by filtration. The remaining hexane layer was dried over Na2SO4 and residual solvent was removed by evaporation. The remaining material was then distilled using a 6" spinning band distillation column, to obtain 43.98 g (0.239 mol, 48.4%) of an oil, bp: 65°-72°/13 mm, 1H NMR (90 MHz, CDCl3): δ0.65 (d, J=6.6 Hz, 2), 0.93 (d, J=6.6 Hz, 6), 1.25 (s, 12), 1.86 (hep, J=6.6 Hz, 1); Anal. Calcd. for C10H21O2B: C, 65.25; H, 11.50; B, 5.87; Found: C, 65.07, H, 11.52; B, 6.01.

Provenance & Evidence