2-Methyl-2-butene → 5-Bromo-2-chloro-3,4-dimethoxybenzoic acid

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Reaction Steps

To the mixture of aldehyde 157 (11.1 g, 39.4 mmol), 2-methyl-2-butene (105 mL, 985 mmol) in t-BuOH (300 mL) was added KH2PO4 (38 g, 276 mmol). NaClO2 (32 g, 355 mmol, dissolved in H2O (160 mL)) was added to the reaction mixture. The mixture was stirred at r.t. for 15 hours. The mixture was evaporated in vacuo to remove the solvent. The residue was extracted with EtOAc/aq. 5% HCl solution (500 mL/300 mL). The organic layer was dried over MgSO4, filtered, and concentrated in vacuo to provide the title compound 158 (11.6 g, 99%).

Provenance & Evidence