Cesium carbonate → Methyl 3-bromo-5-(2-oxopyrrolidin-1-yl)benzoate

Participants

Reaction Conditions

Reaction Steps

A flask was charged under nitrogen with 3-bromo-5-iodo-benzoic acid methyl ester (D8a) (14.8 g, 43.4 mmol, 1 equiv), Cs2CO3 (21 g, 65 mmol, 1.5 equiv), tris(dibenzylideneacetone)dipalladium(0) (794 mg, 0.87 mmol, 0.02 equiv), Xantphos (1.5 g, 2.6 mmol, 0.06 equiv) and dioxan (150 ml). Pyrrolidin-2-one (5 ml, 5.54 mmol, 1.5 equiv) was then added via syringe and the resulting mixture was stirred at 55° C. for 5 days then cooled to room temperature and concentrated in vacuo. The residue was partitioned between H2O and AcOEt and the aqueous phase was re-extracted with AcOEt. The combined organic solutions were dried over MgSO4 and concentrated in vacuo to give a solid residue. Purification of the residue by flash chromatography on silica gel (iso-hexane/AcOEt: 4/1 to 1/1) gave 3-bromo-5-(2-oxo-pyrrolidin-1-yl)-benzoic acid methyl ester (D9a) (6.4 g, 50%) as a white solid. [M+H]+=299.9, RT=2.95 min

Provenance & Evidence