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

HRID 1959936Notes

Reaction equation

HRID 1959936 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-4a0390fa00f34e1986b15ae80b759ab1
Source dataset
uspto-grants-2013_04
Patent number
US08410265B2

Reaction notes

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