A solution of N-acetylmorpholine (1.72 g, 13.3 mmol, 2 eq) in 30 ml dry tetrahydrofuran under nitrogen was cooled in an acetone/dry ice bath (−78° C.) and treated with LDA (10 ml, 2M solution in THF, 3 eq). The reaction mixture was stirred for 60 minutes then 2-hydroxy-3-trifluoromethanesulfonyloxy-benzoic acid methyl ester [α] (2 g, 6.6 mmol, 1 eq as a solution in 10 ml dry THF) was added. The reaction mixture was allowed to warm from −78° C. to room temperature and stirred over night. The reaction was diluted with water (4 ml) followed by 2M hydrochloric acid (40 ml), then extracted three times with dichloromethane. The extracts were combined, washed with brine, dried with magnesium sulphate, filtered and evaporated. The crude product was purified by flash chromatography eluting with ethyl acetate to afford trifluoro-methanesulfonic acid 2-hydroxy-3-(3-morpholin-4-yl-3-oxo-propionyl)-phenyl ester [D]. Yield 1.06 g, 40%
