Triphenylphosphine → tert-butyl (R)-2-(3-benzyloxycarbonylamino-6-bromo-2-tert-butoxycarbonylphenoxymethyl)-azetidine-1-carboxylate

Participants

Reaction Steps

Disopropyl azodicarboxylate (0.717 g) was added to a solution of tert-butyl 6-benzyloxycarbonylamino-3-bromo-2-hydroxybenzoate (Intermediate 48, 1.25 g), tert-butyl (R)-2-hydroxymethylazetidine-1-carboxylate (0.665 g) and triphenylphosphine (0.93 g) in anhydrous THF (20 mL) and the resultant mixture was stirred at room temperature for 30 minutes. The solution 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 0-20% to give tert-butyl (R)-2-(3-benzyloxycarbonylamino-6-bromo-2-tert-butoxycarbonylphenoxymethyl)-azetidine-1-carboxylate (1.74 g) as a colourless gum.

Provenance & Evidence