Triphenylphosphine → ((3S*,4R*)-1-benzyl-4-{[isopropyl-(2-nitro-benzenesulfonyl)-amino]-methyl}-pyrrolidin-3-ylmethyl)-isopropyl-carbamic acid tert-butyl ester

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Reaction Steps

To a solution of ((3S*,4R*)-1-benzyl-4-hydroxymethyl-pyrrolidin-3-ylmethyl)-isopropyl-carbamic acid tert-butyl ester (0.60 g, 1.66 mmol), N-isopropyl-2-nitro-benzenesulfonamide (0.49 g, 1.99 mmol), and PPh3 (0.52 g, 1.99 mmol) in toluene (15 mL), is added dropwise diisopropyl azodicarboxylate (0.39 mL, 1.99 mmol) at 0° C. under a nitrogen atmosphere. The solution is stirred for 1 h at room temperature, and then heated at 65° C. for 1 h. The reaction mixture is concentrated. The crude material is used purified by flash chromatography on silica gel (eluent: c-hexane/AcOEt 3:7) to give the crude product. To the solid product is added a mixture of Et2O/hexane (1:1) and the resulting suspension is filtered. The solid is washed with Et2O/hexane (1:1) solution, and then the combined filtrate is concentrated to give a titled product. TLC, Rf (AcOEt)=0.61. MS (LC-MS): 589.3 [M+H]+; tR (HPLC, C18 column, 10-100% CH3CN/H2O/5 min, 100% CH3CN/2.5 min, CH3CN and H2O containing 0.1% TFA, flow: 1.5 mL/min): 6.39 min.

Provenance & Evidence