Sulfuric Acid → 2-(Cyclohexylmethyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

HRID 1681127Notes

Reaction equation

HRID 1681127 reaction equation
[CH:1]1([CH2:7]Br)[CH2:6][CH2:5][CH2:4][CH2:3][CH2:2]1.[Mg].[B:10](OC)(OC)OC.OS(O)(=O)=O.[OH:22][C:23]([C:26]([OH:29])([CH3:28])[CH3:27])([CH3:25])[CH3:24]>C(OCC)C.CO>[CH:1]1([CH2:7][B:10]2[O:29][C:26]([CH3:28])([CH3:27])[C:23]([CH3:25])([CH3:24])[O:22]2)[CH2:6][CH2:5][CH2:4][CH2:3][CH2:2]1

Participants

8

Reactant 5

HCID 1118Sulfuric AcidHCID 6425PinacolHCID 8470Trimethyl borateHCID 137636Cyclohexane, (bromomethyl)-HCID 5462224Magnesium2×

Product 1

HCID 144250212-(Cyclohexylmethyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 3283Diethyl EtherSolvent4×

Procedure

62.9 ml of cyclohexylmethyl bromide are slowly added dropwise to 12.0 g of magnesium and 200 ml of diethyl ether. After the magnesium has dissolved, the solution of the Grignard compound is added dropwise to a solution of 50.3 ml of trimethyl borate in 100 ml of diethyl ether which has been precooled to -78° C. in such a way that the temperature does not rise above -55° C., and the mixture is then stirred at R.T. for 2 h. Then, while cooling in ice, 113 ml of 40% strength H2SO4 are added in such a way that the internal temperature does not rise above 25° C. 53.2 g of pinacol in 100 ml of diethyl ether are now poured in, and the diethyl ether together with the biproduct methanol are removed in a rotary evaporator. The pH is then adjusted with NaHCO3 to 8, the mixture is extracted 3 times with 200 ml of MTB, the organic phase is dried over Na2SO4, the solvent is removed in vacuo, and the residue is distilled under high vacuum. 49.7 g of the title compound are obtained as a colorless oil. ##EQU5##

Workup

  1. customhas been precooled to -78° C. in such
  2. customdoes not rise above -55° C.
  3. temperatureThen, while cooling in ice
  4. customdoes not rise above 25° C
  5. customare removed in a rotary evaporator
  6. extractionthe mixture is extracted 3 times with 200 ml of MTB
  7. dry with materialthe organic phase is dried over Na2SO4
  8. customthe solvent is removed in vacuo
  9. distillationthe residue is distilled under high vacuum

Sources & evidence

ORD record
ord-dd7932e3dc154cc682f4dce7812800b8
Source dataset
uspto-grants-1992_12
Patent number
US05169841

Reaction notes

Loading…