Triethylamine → 4-Nitrophenyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl carbonate

HRID 336114Notes

Reaction equation

HRID 336114 reaction equation
[OH:1][CH2:2][C:3]1[CH:8]=[CH:7][C:6]([B:9]2[O:17][C:14]([CH3:16])([CH3:15])[C:11]([CH3:13])([CH3:12])[O:10]2)=[CH:5][CH:4]=1.C(N(CC)CC)C.Cl[C:26]([O:28][C:29]1[CH:34]=[CH:33][C:32]([N+:35]([O-:37])=[O:36])=[CH:31][CH:30]=1)=[O:27]>C1COCC1.CCOC(C)=O>[C:26](=[O:27])([O:1][CH2:2][C:3]1[CH:4]=[CH:5][C:6]([B:9]2[O:17][C:14]([CH3:16])([CH3:15])[C:11]([CH3:13])([CH3:12])[O:10]2)=[CH:7][CH:8]=1)[O:28][C:29]1[CH:30]=[CH:31][C:32]([N+:35]([O-:37])=[O:36])=[CH:33][CH:34]=1

Participants

6

Reactant 3

HCID 8471TriethylamineHCID 821294-Nitrophenyl chloroformateHCID 114020504-(Hydroxymethyl)benzeneboronic acid pinacol ester

Product 1

HCID 585607534-Nitrophenyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl carbonateYield 60%

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolventHCID 8857Ethyl AcetateSolvent

Procedure

4-(Hydroxymethyl)phenylboronic acid pinacol ester (0.5 g, 2.1 mmol) was dissolved in 20 mL of dry THF. Triethylamine (0.6 mL, 4.3 mmol) was added followed by 4-nitrophenyl chloroformate (0.47 g, 2.3 mmol) and the reaction was allowed to stir at room temperature for 1 h. The reaction was diluted with EtOAc and washed with 1.0 M HCl followed by saturated NaHCO3. The organic layer was dried over MgSO4, filtered and concentrated. Compound B2a was purified on a silica gel column eluting with 5% EtOAc in hexanes to give 0.51 g (1.3 mmol, 60% yield) as a white solid. 1H NMR (400 MHz, CDCl3) δ=8.25 (d, J=9.2 Hz, 2H), 7.85 (d, J=8.0 Hz, 2H), 7.43 (d, J=8.0 Hz, 2H), 7.36 (d, J=9.2 Hz, 2H), 5.31 (s, 2H), 1.35 (s, 12H). 13C NMR (100 MHz, CDCl3) δ=155.7, 152.7, 145.6, 137.2, 135.4, 127.9, 125.5, 122.0, 84.2, 71.0, 25.1. ESI-MS(+): m/z 417.19 [M+NH4]+, 422.20 [M+Na]+.

Workup

  1. washwashed with 1.0 M HCl
  2. dry with materialThe organic layer was dried over MgSO4
  3. filtrationfiltered
  4. concentrationconcentrated
  5. customCompound B2a was purified on a silica gel column
  6. washeluting with 5% EtOAc in hexanes
  7. customto give 0.51 g (1.3 mmol, 60% yield) as a white solid

Sources & evidence

ORD record
ord-e0f28dd26db24cfcb5532fab383edac8
Source dataset
uspto-grants-2014_11
Patent number
US08889638B2

Reaction notes

Loading…