tert-Butanol → Benzyl ((2R,3S)-2-((1-(2-((tert-butoxycarbonyl)amino)ethyl)-1H-1,2,3-triazol-4-yl)methyl)-1-(2,4-dimethoxybenzyl)-4-oxoazetidin-3-yl)(4-methoxybenzyl)carbamate

Participants

Reaction Steps

To a solution of benzyl ((3S,4R)-1-(2,4-dimethoxybenzyl)-2-oxo-4-(prop-2-yn-1-yl)azetidin-3-yl)(4-methoxybenzyl)carbamate (95.6 mg, 0.18 mmol) in a mixture of DMSO (1.2 mL), tert-butanol (1.2 mL) and water (1.2 mL), was added copper(II) sulfate pentahydrate (4.5 mg, 0.018 mmol), sodium L-ascorbate (35.8 mg, 0.18 mmol) and N-Boc-2-azidoethylamine (76 mg, 0.39 mmol). After stirring for 12 h, more copper(II) sulfate pentahydrate (10.6 mg, 0.23 equiv), sodium L-ascorbate (37.4 mg, 1.04 equiv) and N-Boc-2-azidoethylamine (82.1 mg, 2.44 equiv) were added. After stirring for 4 days total, the reaction mixture was diluted with EtOAc and water. The layers were separated, and the aqueous layer was extracted with EtOAc (2×). Combined organic layers were washed with LiCl (5% aq), brine, dried over Na2SO4, filtered and concentrated in vacuo. The residue was purified via silica gel chromatography (EtOAc-Hep, 0-40%) to afford the title compound (57.2 mg, 44%). LCMS: Rt=1.06 min, m/z=715.5 (M+1) Method 2m_acidic.

Provenance & Evidence