Triisopropyl borate → 5-Cyanothiophene-2-boronic acid

HRID 1484907Notes

Reaction equation

HRID 1484907 reaction equation
[S:1]1[CH:5]=[CH:4][CH:3]=[C:2]1[C:6]#[N:7].C([O:11][B:12](OC(C)C)[O:13]C(C)C)(C)C.C[Si](C)(C)[N-][Si](C)(C)C.[K+]>C1COCC1>[C:6]([C:2]1[S:1][C:5]([B:12]([OH:13])[OH:11])=[CH:4][CH:3]=1)#[N:7]

Participants

5

Reactant 3

HCID 21531Triisopropyl borateHCID 660872-ThiophenecarbonitrileHCID 3251421Potassium bis(trimethylsilyl)amide

Product 1

HCID 41987435-Cyanothiophene-2-boronic acidYield 528.1%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

To a solution of compound thiophene-2-carbonitrile (10 g, 9.16 mmol, 1.0 eq) and tri-iso-propylborate (23 mL, 100 mmol, 1.09 eq) in dry THF (300 mL) under nitrogen at −78° C., potassium hexamethyldisilazide (1 M in THF, 100 mL, 100 mmol, 1.09 eq) was added dropwise. After 1 h, the reaction was quenched with 1 N HCl (200 mL), stirred for 30 min and extracted with ethyl acetate. The combined organic layers were washed with water, dried (Na2SO4), filtered and evaporated and crystallized with petroleum ether/ethyl acetate to afford the product compound 5-cyanothiophen-2-ylboronic acid (7.4 g, 53%). LC-MS (m/z)=153.9 [M+H]+

Workup

  1. customthe reaction was quenched with 1 N HCl (200 mL)
  2. extractionextracted with ethyl acetate
  3. washThe combined organic layers were washed with water
  4. dry with materialdried (Na2SO4)
  5. filtrationfiltered
  6. customevaporated
  7. customcrystallized with petroleum ether/ethyl acetate

Sources & evidence

ORD record
ord-f4281c46171c491798f091d5f82b59ab
Source dataset
uspto-grants-2016_08
Patent number
US09422271B2

Reaction notes

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