3,5-Dihydroxy-3-methylpentanoic acid methyl ester → 5-Bromo-3-hydroxy-3-methylpentanoic acid methyl ester

Participants

Reaction Steps

To a solution of 3.00 g. (18.5 mmol) 3,5-dihydroxy-3-methylpentanoic acid methyl ester in 15 ml. anhydrous tetrahydrofuran is added a solution of 8.90 g. (18.5 mmol) benzyl triphenoxyphosphonium bromide in 10 ml. tetrahydrofuran and the reaction mixture is stirred for 15 hours at ambient temperature. Thereafter, it is evaporated in a vacuum, the bath temperature thereby being kept below 15° C. The oily residue obtained is chromatographed on 700 g. silica gel 60 with n-hexane/tert.-butanol (6:1 v/v) as elution agent. After removal of the elution agent, there is obtained 1.32 g. (32% of theory) of the desired product in the form of a bright yellow oil; nD20 =1.4734; RF =0.65 (silica gel; n-hexane/tert.-butanol (6:1 v/v)).

Provenance & Evidence