Chlorotrimethylsilane → (3S)-3-mercapto-1-(4-nitrobenzyloxycarbonyl)pyrrolidine

Participants

Reaction Steps

A suspension of mercaptoamine hydrochloride 7 (589 mg, 4.22 mmol) in anhydrous MeCN (3.2 ml) was stirred under a N2 atmosphere with ice-bath cooling. The mixture was treated with N,N-diisopropylethylamine (1.69 ml, 9.71 mmol), stirred 5 min, and treated with chlorotrimethyl silane (0.70 ml, 5.52 mmol). After stirring 10 more minutes in the cold, the mixture was treated with a solution of p-nitrobenzyl chloroformate (910 mg, 4.22 mmol) in MeCN (1.0 ml) followed by more N,N-diisopropylethylamine (0.74 ml, 4.25 mmol). The resulting mixture was stirred in the cold for 15 minutes and at room temperature for 1 hour. The reaction mixture was diluted with EtOAc, washed with H2O, 1N HCl, 5% aqueous NaHCO3 and brine, dried with MgSO4, filtered, and evaporated (i.v.) to a yellow gum. The crude product was chromatographed on EM silica gel 60 (60 g) using 25:1 CH2Cl2 --EtOAc as eluting solvent to afford derivative 25 (858 mg, 72%) as a pale yellow oil.

Provenance & Evidence