Sulfuric Acid → 1-(1,1-Dimethylethyl) 2-borono-6-[[(1,1-dimethylethyl)dimethylsilyl]oxy]-1H-indole-1-carboxylate

HRID 2234087Notes

Reaction equation

HRID 2234087 reaction equation
[C:1]([O:5][C:6]([N:8]1[C:16]2[C:11](=[CH:12][CH:13]=[C:14]([O:17][Si:18]([C:21]([CH3:24])([CH3:23])[CH3:22])([CH3:20])[CH3:19])[CH:15]=2)[CH:10]=[CH:9]1)=[O:7])([CH3:4])([CH3:3])[CH3:2].C([Li])(C)(C)C.C[O:31][B:32](OC)[O:33]C.[Cl-].[NH4+].OS([O-])(=O)=O.[K+].OS(O)(=O)=O>O1CCCC1.CCCCC.CCOCC>[C:1]([O:5][C:6]([N:8]1[C:16]2[C:11](=[CH:12][CH:13]=[C:14]([O:17][Si:18]([C:21]([CH3:24])([CH3:23])[CH3:22])([CH3:19])[CH3:20])[CH:15]=2)[CH:10]=[C:9]1[B:32]([OH:33])[OH:31])=[O:7])([CH3:4])([CH3:3])[CH3:2]

Participants

10

Reactant 6

HCID 1118Sulfuric AcidHCID 8470Trimethyl borateHCID 25517Ammonium ChlorideHCID 516920Potassium bisulfateHCID 16654571tert-butyl 6-{[tert-butyl(dimethyl)silyl]oxy}-1H-indole-1-carboxylateHCID 178418306HCID 178418306, compound

Product 1

HCID 230924981-(1,1-Dimethylethyl) 2-borono-6-[[(1,1-dimethylethyl)dimethylsilyl]oxy]-1H-indole-1-carboxylateYield 56%

Reagents, catalysts & solvents 3

HCID 3283Diethyl EtherSolventHCID 8003PentaneSolventHCID 8028TetrahydrofuranSolvent

Conditions

Temperature
-78 °C

Procedure

To a solution of 1 g 1-(tert-butoxycarbonyl)-6-(tert-butyldimethylsiloxy)indole in 15 mL anhydrous tetrahydrofuran at −78° C. under nitrogen is added tert-butyllithium (2.30 mL of a 1.5 M solution in pentane) over 3 min and the reaction stirred at −78° C. After 32 min, 0.66 mL trimethylborate are added in one portion and the reaction stirred at 0° C. After 2 h, 9 mL saturated aqueous ammonium chloride are added, the mixture diluted with 25 mL ether, and stirred at ambient temperature. The reaction is acidified with 4 mL of a solution made from 10% aqueous KHSO4 (60 mL) and concentrated H2SO4 (2 mL). After stirring for 15 min, the layers are separated and the organics ished with water (15 mL) and brine (15 mL) successively, dried (Na2SO4), and the solvent removed under reduced pressure to yield a partially solidified material. The material is ished with hot hexanes (5 mL) and filtered. The collected solid is ished with hexanes (2×5 mL) to give 635 mg (56%) of 1-(tert-butoxycarbonyl)-6-(tert-butyldimethylsiloxy)indole-2-boronic acid as a white powder.

Workup

  1. stirringthe reaction stirred at 0° C
  2. waitAfter 2 h
  3. stirringstirred at ambient temperature
  4. stirringAfter stirring for 15 min
  5. customthe layers are separated
  6. dry with materialdried (Na2SO4)
  7. customthe solvent removed under reduced pressure
  8. customto yield a partially solidified material
  9. filtrationfiltered

Sources & evidence

ORD record
ord-d88f702fa214446badfc496734782990
Source dataset
uspto-grants-2010_05
Patent number
US07709466B2

Reaction notes

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