Triphenylphosphine → HCID 56611422, compound

Participants

Reaction Steps

A stirred solution of the γ-lactone of (2S,4S,5S)-4,5-dihydroxy-2-isopropyl-7-methyloctanoic acid from Preparation IIIA (0.214 g., 1 mmol) and triphenylphosphine (0.289 g., 1.1 mmol) in benzene (3 ml) is cooled in an ice bath and treated during 5-10 minutes with N-bromosuccinimide (0.196 g., 1.1 mmol). The mixture is kept cold for an additional 30 minutes and then at ambient temperature for 4 hours. It is diluted with Et2O and filtered. The filtrate is con-centrated and the residue chromatographed on silica gel (100 g.) with 7.5% EtOAc-hexane. The product, the γ-lactone of (2S,4S,5R)-5-bromo-4-hydroxy-2-isopropyl-7-methyloctanoic acid, thus obtained was crystallized from cold pentane to give 0.061 g., m.p. 62.5°-63.5° C. and 0.054 g., m.p. 60°-62.5° C.

Provenance & Evidence