Triphenylphosphine → tert-butyl (R)-2-[6-bromo-3-bis-(tert-butoxycarbonyl)amino-2-methoxycarbonylphenoxymethyl]pyrrolidine-1-carboxylate

Participants

Reaction Steps

Diisopropyl azodicarboxylate (1.21 g) was added to a solution of methyl 3-bromo-6-bis-(tert-butoxycarbonyl)amino-2-hydroxybenzoate (Intermediate 9, 2.23 g), tert-butyl (R)-2-hydroxymethylpyrrolidine-1-carboxylate (1.11 g) and triphenylphosphine (1.57 g) in anhydrous THF (25 mL) and the reaction mixture was stirred at room temperature for 30 minutes, then left to stand overnight. The mixture was concentrated in vacuo and the residue was purified by chromatography on silica, eluting with a mixture of ethyl acetate and cyclohexane with a gradient of 0-30% to give tert-butyl (R)-2-[6-bromo-3-bis-(tert-butoxycarbonyl)amino-2-methoxycarbonyl-phenoxymethyl]pyrrolidine-1-carboxylate (3.17 g) as a colourless gum.

Provenance & Evidence