Hydrochloric Acid → 4,4,5,5-Tetramethyl-2-(pent-1-yn-1-yl)-1,3,2-dioxaborolane

HRID 1627979Notes

Reaction equation

[Li][CH2:2][CH2:3][CH2:4][CH3:5].C(O[B:10]1[O:14][C:13]([CH3:16])([CH3:15])[C:12]([CH3:18])([CH3:17])[O:11]1)(C)C.[C-:19]#[C-].[Li+].[Li+].Cl>C1COCC1>[CH3:16][C:13]1([CH3:15])[C:12]([CH3:17])([CH3:18])[O:11][B:10]([C:5]#[C:4][CH2:3][CH2:2][CH3:19])[O:14]1

Participants

Conditions

Temperature: -78 °C

Procedure

To a stirred solution of IIc′ (5 mL, 51 mmol) in dry THF (25 mL) at −78° C. was added n-BuLi (2.5 M in n-hexane, 22.4 mL, 56 mmol). Another flask was charged with 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (10.4 mL, 51 mmol) in dry THF (50 mL) under argon atmosphere, and the reaction mixture was cooled to −78° C. The lithium acetylide from the first flask, which was cooled to −78° C., was slowly added to the second by a double-ended needle. The mixture was stirred at −78° C. for 2 hours, after which anhydrous HCl (56 mmol) was added. Then, reaction mixture was warmed to room temperature. After removal of the precipitated LiCl by filtration and removal of solvents under reduced pressure, the residue was purified by distillation (115-125° C./15 mbar) to afford IIIc (6.3 g, 64%) as an oil.

Workup

additionwas slowly added to the second by a double-ended needle
customThen, reaction mixture
temperaturewas warmed to room temperature
customAfter removal of the precipitated LiCl
filtrationby filtration and removal of solvents under reduced pressure
distillationthe residue was purified by distillation (115-125° C./15 mbar)
customto afford IIIc (6.3 g, 64%) as an oil

Sources & evidence

ORD record: ord-f9e45b906639456d84bf829c771e3700
Source dataset: uspto-grants-2014_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08785674B2

Reaction notes

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