Barbier Reaction

The Barbier reaction is an organometallic reaction between an alkyl halide, a carbonyl group, and a metal to give a primary, secondary, or tertiary alcohol.

Barbier Reaction

Barbier Reaction

Reaction Mechanism

Barbier Reaction
Barbier Reaction

The mechanism of the formation of the organometallic reagent is identical to the formation of a Grignard reagent. The reaction involves a single electron transfer from the metal surface to the alkyl halide. Then, the addition of the Grignard reagent to the carbonyl compound  may take place via a concerted process or a radical pathway.

Experimental Procedure

Barbier Reaction

To a solution of the aldehyde (2.24 g, 3.83 mmol) in THF/Et2O/H2O (8:1:1, 45 mL) was added 2,3-dibromopropene (11.5 mmol) and Sn powder (11.5 mmol) at room temperature. The resulting mixture was stirred for 2 days till the starting material was fully consumed. The reaction was quenched with sat. aq. NaHCO3 and extracted with EtOAc. The combined organic layers were dried over Na2SO4 and concentrated under reduced pressure to give the crude product, which was used in the next step without further purification.

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