Trimethyl borate → 2-Formyl-1-methyl-phenylboronic acid

HRID 2215984Notes

Reaction equation

HRID 2215984 reaction equation
Br[C:2]1[CH:7]=[CH:6][CH:5]=[C:4]([CH:8](OC)[O:9]C)[C:3]=1[CH3:13].C([Li])CCC.C[O:20][B:21](OC)[O:22]C>CC(C)=O.Cl>[CH:8]([CH:4]1[CH:5]=[CH:6][CH:7]=[CH:2][C:3]1([B:21]([OH:22])[OH:20])[CH3:13])=[O:9]

Participants

6

Reactant 3

HCID 8470Trimethyl borateHCID 218860701-Bromo-3-dimethoxymethyl-2-methyl-benzeneHCID 178418339Butyllithium

Product 1

HCID 866011742-Formyl-1-methyl-phenylboronic acidYield 38%

Reagents, catalysts & solvents 2

HCID 180AcetoneSolventHCID 313Hydrochloric AcidSolvent

Procedure

The 1-bromo-3-dimethoxymethyl-2-methyl-benzene ((Example 6: step c) 500 mg, 2 mmol), butyllithium (2.5 M, 1 mL, 2.5 mmol), and trimethylborate (2.3 mL, 20 mmol) were reacted as in Example 5: step b. After aqueous workup, the residue was dissolved in acetone (18 mL) and HCl (1N, 2 mL). After standing for 18 h at rt, the volatile components were removed in vacuo and the residue was purified by SiO2 flash chromatography (25–40% EtOAc in hexanes) to give the title compound (126 mg, 38%). The title compound exists as a mixture of boronic acids and anhydrides in CDCl3, therefore the reported NMR signals represent pairs or groups of related signals. 1H-NMR (CDCl3): δ 10.44 (s, 1H), 8.38 (dd, 1H, J=1.4, 7.4 Hz), 7.49 (t, 1H, J=7.5 Hz), 3.12 (s, 3H).

Workup

  1. customthe volatile components were removed in vacuo
  2. customthe residue was purified by SiO2 flash chromatography (25–40% EtOAc in hexanes)

Sources & evidence

ORD record
ord-ec1b9a08567c428999e3322a3b540f47
Source dataset
uspto-grants-2006_09
Patent number
US07109354B2

Reaction notes

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