Pinacol → 2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

HRID 880594Notes

Reaction equation

HRID 880594 reaction equation
[B:1]([O-:7])([O-:6])[O:2][CH:3]([CH3:5])[CH3:4].O[C:9]([C:12](O)([CH3:14])[CH3:13])([CH3:11])[CH3:10]>>[CH:3]([O:2][B:1]1[O:7][C:12]([CH3:14])([CH3:13])[C:9]([CH3:11])([CH3:10])[O:6]1)([CH3:5])[CH3:4]

Participants

3

Reactant 2

HCID 6425PinacolHCID 71368315Isopropylborate

Product 1

HCID 50177412-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolaneYield 87.5%

Procedure

A 5 L 4-neck flask equipped with a reflux condenser, mechanical stirrer, N2 inlet, and thermowell was flushed well with N2 and charged with isopropyl borate (2.673 L, 11.5 mol, 1.15 equiv) and pinacol (1.179 kg, 10 mol). The resulting mixture was heated at reflux (80-85°) for overnight. The mixture was then cooled to room temperature, transferred to a 5 L 4-neck flask equipped with a 24 inch Vigreux column, magnetic stirrer, and thermowell. The mixture was distilled at atmospheric pressure under nitrogen. After the low boiling fraction (bp 90-180°) which contained predominately 2-propanol and isopropyl borate (GC analysis) was removed, the completed distillation afforded 2-isopropoxy-4,4,5,5-tetramethyl[1,3,2]dioxaborolane (10, 1.628 kg, 1.86 Kg theoretical, 87.5%) as a colorless liquid (bp 180-185° C. with GC purity >97.5%). This material was stored in Sure/Seal bottles to minimize hydrolysis.

Workup

  1. customA 5 L 4-neck flask equipped with a reflux condenser, mechanical stirrer, N2 inlet
  2. customthermowell was flushed well with N2
  3. temperatureThe resulting mixture was heated
  4. temperatureat reflux (80-85°) for overnight
  5. customequipped with a 24 inch Vigreux column, magnetic stirrer
  6. distillationThe mixture was distilled at atmospheric pressure under nitrogen
  7. customwas removed
  8. distillationthe completed distillation

Sources & evidence

ORD record
ord-f7145ad2ad88482ebaf5d2d7982d7b7b
Source dataset
uspto-grants-2015_03
Patent number
US08993582B2

Reaction notes

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