(S)-4-(tert-butyldimethylsilyloxy)butan-2-ol → (S)-4-(tert-butyldimethylsilyloxy)butan-2-yl 2-methoxy-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenylcarbamate

HRID 245717Notes

Reaction equation

HRID 245717 reaction equation
[Si:1]([O:8][CH2:9][CH2:10][C@@H:11]([OH:13])[CH3:12])([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2].[N:14]([C:17]1[CH:22]=[CH:21][C:20]([B:23]2[O:27][C:26]([CH3:29])([CH3:28])[C:25]([CH3:31])([CH3:30])[O:24]2)=[CH:19][C:18]=1[O:32][CH3:33])=[C:15]=[O:16]>ClCCl.CN(C)C1C=CN=CC=1>[CH3:33][O:32][C:18]1[CH:19]=[C:20]([B:23]2[O:27][C:26]([CH3:28])([CH3:29])[C:25]([CH3:30])([CH3:31])[O:24]2)[CH:21]=[CH:22][C:17]=1[NH:14][C:15](=[O:16])[O:13][C@H:11]([CH2:10][CH2:9][O:8][Si:1]([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2])[CH3:12]

Participants

5

Reactant 2

HCID 10998136(S)-4-(tert-butyldimethylsilyloxy)butan-2-olHCID 866746582-(4-Isocyanato-3-methoxyphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

Product 1

HCID 67365296(S)-4-(tert-butyldimethylsilyloxy)butan-2-yl 2-methoxy-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenylcarbamateYield 67.2%

Reagents, catalysts & solvents 2

HCID 142844-(Dimethylamino)pyridineCatalystHCID 6344DichloromethaneSolvent

Conditions

Temperature
40 °C

Procedure

To (S)-4-(tert-butyldimethylsilyloxy)butan-2-ol (1.649 mmol, 337 mg) in dichloromethane (4 ml) were added mol sieves (4A), 2-(4-isocyanato-3-methoxyphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1.374 mmol, 378 mg) and 4-dimethylaminopyridine (0.275 mmol, 33.6 mg) were added and the mixture was stirred at 40° C. (oil bath temperature) for 18 hours. The mol sieves were removed by filtration and the filtrate washed with water, dried (sodium sulfate) and concentrated in vacuo to give a crude product which was purified by column chromatography (silica gel, heptanes with gradient 10% to 50% of ethyl acetate) to afford (S)-4-(tert-butyldimethylsilyloxy)butan-2-yl 2-methoxy-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenylcarbamate (443 mg). Tetrabutylammonium fluoride (1M in tetrahydrofuran, 1.22 mmol, 1.22 ml) was added to (S)-4-(tert-butyldimethylsilyloxy)butan-2-yl 2-methoxy-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenylcarbamate (240 mg) in tetrahydrofuran (1 ml) at room temperature. After 20 hours water was added to the reaction mixture, extracted with dichloromethane, the organic extract dried (sodium sulfate) and concentration in vacuo to yield (S)-4-hydroxybutan-2-yl 2-methoxy-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenylcarbamate (268 mg) which was used in the next step without further purification.

Workup

  1. additionwere added
  2. customThe mol sieves were removed by filtration
  3. washthe filtrate washed with water
  4. dry with materialdried (sodium sulfate)
  5. concentrationconcentrated in vacuo
  6. customto give a crude product which
  7. customwas purified by column chromatography (silica gel, heptanes with gradient 10% to 50% of ethyl acetate)

Sources & evidence

ORD record
ord-740425fee6084b7791f0fbed821e3491
Source dataset
uspto-grants-2014_02
Patent number
US08658794B2

Reaction notes

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