p-Toluenesulfonic acid monohydrate → [(Z)-4-((R)-2-hydroxymethyl-6-oxo-piperidin-1-yl)-but-2-enyloxy]-acetic acid ethyl ester

Participants

Reaction Steps

p-Toluenesulfonic acid hydrate (267 mg, 1.40 mmol) was added to a solution of {(Z)-4-[(R)-2-(1-ethoxyethoxymethyl)-6-oxo-piperidin-1-yl]-but-2-enyloxy}-acetic acid ethyl ester (from example 50, step 2, 477 mg, 1.33 mmol) in EtOH (6 mL). After 18 h at rt, the reaction was concentrated in vacuo and quenched with saturated aqueous NaHCO3 (20 mL). The mixture was extracted with CH2Cl2 (3×15 mL). The combined organic phase was dried (Na2SO4), filtered and concentrated in vacuo. Purification of the residue by flash column chromatography on silica gel (CH2Cl2→3% MeOH/CH2Cl2, gradient) afforded 290 mg (76%) of [(Z)-4-((R)-2-hydroxymethyl-6-oxo-piperidin-1-yl)-but-2-enyloxy]-acetic acid ethyl ester.

Provenance & Evidence