2-Methylbenzaldehyde → α,α-Difluoro-β-hydroxy-2-methylbenzenepropanoic acid

Participants

Reaction Steps

A solution of ethyl bromodifluoroacetate (5.6 g) and 2-methylbenzaldehyde (3 g) in THF (25 mL) is added dropwise to a refluxing suspension of activated zinc dust (2.1 g) in THF (25 mL) and refluxing continued for a further 4 hours. The reaction is allowed to cool to ambient temperature, filtered through hyflo and concentrated in vacuo to give a yellow solid. The solid is taken up in ethyl acetate (50 mL) and washed with brine which leads to the formation of a white precipitate which is filtered off then partitioned between ethyl acetate (50 mL) and 1 N HCl (50 mL). The organic phase is washed with water, dried over magnesium sulphate, filtered and concentrated in vacuo to give (RS)-2,2-difluoro-3-hydroxy-3-(2-methylphenyl)propanoic acid as a yellow solid (2.4 g)

Provenance & Evidence