Methanesulfonic Acid → (3S,5S)-methanesulfonic acid 5-benzyloxymethyl-1-(naphthalene-2-sulfonyl)-pyrrolidin-3-yl ester

Participants

Reaction Steps

To a suspension of methanesulphonic acid (0.96 g) in toluene (30 ml) was added triethylamine (1.40 ml) and triphenylphosphine (2.72 g) at 0-5° C. The suspension was stirred for 5 minutes, and (3R,5S)-5-benzyloxymethyl-1-(naphthalene-2-sulfonyl)-pyrrolidin-3-ol (3.46 g) dissolved in toluene (20 ml) was added dropwise in 5 minutes, followed by diisipropyl azodicarboxylate (2.0 ml). The reaction mixture was stirred for 3 h at 85° C., poured onto ice/water and extracted with ethy acetate. The organic phase was washed with 10% KHSO4— and NaCl solutions, dried over magnesium sulphate and concentrated. The residue was chromatographed on silica gel using EtOAc/hexane 1:2 and 1:1 as eluents to obtain (3S,5S)-methanesulfonic acid 5-benzyloxymethyl-1-(naphthalene-2-sulfonyl)-pyrrolidin-3-yl ester (3.35 g) as a slightly yellow syrup, MS: 476 (MH+).

Provenance & Evidence