Chlorotrimethylsilane → (S)-3-{3-Benzyloxy-4-[1,1,4-trioxo-5-(2-trimethylsilanylethyl)-1,2,5-thiadiazolidin-2-yl]-phenyl}-2-tert-butoxycarbonylaminopropionic Acid Tert-butyl Ester

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Reaction Steps

To a suspension of zinc powder (645 mg, 9.9 mmol) in DMF (1 mL) under argon is added chlorotrimethylsilane (83 mg, 0.76 mmol) and the mixture is stirred at RT for 30 min. To this is added a solution of (R)-2-tert-butoxycarbonylamino-3-iodopropionic acid tert-butyl ester (1.1 g, 2.96 mmol) in DMF (1.8 mL) dropwise and the mixture is stirred at RT for 30 min. An additional 2.5 mL of DMF is added and any insoluble material is filtered. The filtrate is added to a mixture of 5-(2-benzyloxy-4-iodophenyl)-1,1-dioxo-2-(2-trimethylsilanylethyl)-1,2,5-thiadiazolidin-3-one (900 mg, 1.65 mmol), tri-o-tolylphosphine (100 mg, 0.33 mmol) and Pd2(dba)3 (74 mg, 0.08 mmol) and the mixture is stirred at RT for 90 min. Water is added and the mixture is extracted with EtOAc. The organic phase is washed with water (2×) and brine then is dried over sodium sulfate. The solvent is remover under reduced pressure and the residue is purified by flash chromatography using EtOAc/hexane (10%) as eluent to give the title compound as an off-white solid.

Provenance & Evidence