Triphenylphosphine → (2S,5R)-tert-butyl 5-(N-(allyloxy)-2-nitrophenylsulfonamido)-2-((tert-butyldimethyl-silyloxy)methyl)-4-(dimethylcarbamoyl)-5,6-dihydropyridine-1(2H)-carboxylate

Participants

Reaction Steps

A stirred suspension of (2S,5S)-tert-butyl 2-((tert-butyldimethylsilyloxy)methyl)-4-(dimethylcarbamoyl)-5-hydroxy-5,6-dihydropyridine-1(2H)-carboxylate (Intermediate 137, 3.09 g, 7.45 mmol), N-(allyloxy)-2-nitrobenzenesulfonamide (2.348 g, 9.09 mmol) and triphenylphosphine (2.150 g, 8.20 mmol) in toluene (65 mL) was cooled in a salt-ice-bath and then (E)-diisopropyl diazene-1,2-dicarboxylate (1.588 mL, 8.20 mmol) was added dropwise. The reaction was let warm up to rt and was stirred for an additional 2 h. The solvent was removed and the crude product was loaded onto silica gel, purified via flash chromatography (25-75% EA/Hex) to obtain the desired product (4.0 g, 82%) as an off-white solid.

Provenance & Evidence