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Following the general procedure for the preparation of carboxylic esters from carboxylic acids of Description 15, (2R)-4-[(3-chloropropyl)sulfonyloxy]-3,3-dimethyl-2-(phenylmethoxy)butanoic acid (11) (1.1 g, 2.90 mmol) dissolved in 40 mL of anhydrous dichloromethane (DCM) was reacted with 1.74 mL (3.48 mmol) of oxalyl chloride (2.0 M in DCM). After completion of the reaction, an aliquot (ca. 1.45 mmol) of the acid chloride was reacted with 455 mg (4.41 mmol) of 2-hydroxy-N,N-dimethylacetamide (36b) and 352 μL mL of pyridine (344 mg, 4.35 mmol) in 10 mL of anhydrous dichloromethane (DCM). After work-up, the crude material was purified by silica gel column chromatography using mixtures of ethyl acetate (EtOAc) and hexane (Hxn) as eluent (EtOAc/Hxn=2:3→EtOAc/Hxn=1:1) to provide 200 mg (30% yield) of the title compound (36c) as an opaque, viscous oil. Rf=0.28 (EtOAc/Hxn=1:1). MS (ESI) m/z 464.2 (M+H)+, 486.1 (M+Na)+.

1. customAfter completion of the reaction
2. customAfter work-up, the crude material was purified by silica gel column chromatography