Acetic Acid → 4-Bromoacetyl-3-fluorophenylboronic acid

Participants

Reaction Conditions

Reaction Steps

An oven-dried, 500-milliliter, 3-necked, round-bottomed flask was charged with 5 grams (27.4 millimole) of 4-acetyl-3-fluorophenyl boronic acid and 25 milliliters of methanol under a nitrogen atmosphere. The solution was cooled to 0° C. using an ice bath. To this solution was added 0.2 milliliters (0.55 equivalents) of glacial acetic acid. In a 100 milliliters Erlenmeyer flask was taken 1.27 milliliters (3.95 grams, 24 millimole, 0.9 equivalents) of elemental bromine dissolved in 4 milliliters of cold methanol. The bromine solution was added dropwise to the above solution at 0° C. using an addition funnel. With the addition of Br2, the solution slowly turned light orange and finally to dark orange when addition was complete. After about 5-6 hours, the progress of the reaction was monitored by NMR. Depending on the progress of reaction, another 10-20 mole % of bromine was added after cooling the solution to 0° C. Total reaction time was approximately 24 hours.

Provenance & Evidence