Triphenylphosphine → Tert-butyl 2-(6-bromo-3-[bis-(tert-butoxycarbonyl)amino]-2-methoxycarbonylphenoxymethyl)-2,5-dihydropyrrole-1-carboxylate

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Reaction Steps

Diisopropylazodicarboxylate (1.4 g) was added to a suspension of methyl 3-bromo-6-[bis-(tert-butoxycarbonyl)amino]-2-hydroxybenzoate (Intermediate 13, 2.58 g), tert-butyl 2-hydroxymethyl-2,5-dihydropyrrole-1-carboxylate (Prepared according to Morriello et al, Bioorg. Med. Chem, 2008, 16(5), 2156; 1.27 g) and triphenylphosphine (1.82 g) in anhydrous THF (20 mL) and the mixture was stirred at room temperature overnight. The volatiles were removed in vacuo and the residue was purified by chromatography on silica, eluting with a mixture of ethyl acetate and cyclohexane with a gradient of 5-25% to give tert-butyl 2-(6-bromo-3-[bis-(tert-butoxycarbonyl)amino]-2-methoxycarbonylphenoxymethyl)-2,5-dihydropyrrole-1-carboxylate (4.13 g) as a light brown oil.

Provenance & Evidence