Chlorosulfonic acid → 3-(5-Chlorosulfonyl-2-methoxyphenyl)propionic acid 2-(toluene-4-sulfonyl)ethyl ester

Participants

Reaction Conditions

Reaction Steps

To a mixture of 3-(2-methoxyphenyl)propionic acid 2-(toluene-4-sulfonyl)ethyl ester (Intermediate 59, 5.0 g, 13.8 mmol) and 5 mL of CH2Cl2 was added dropwise chlorosulfonic acid (8.0 g, 69.0 mmol, 5.0 eq) with ice-bath cooling. The mixture was stirred at 0° C. for 30 min. The resulting thick oil was poured onto crushed ice with vigorous stirring. The mixture was extracted with EtOAc. The organic layer was dried over MgSO4, and concentrated by evaporation to give a thick oil, which was purified by column chromatography (CH2Cl2) to yield 3-(5-chlorosulfonyl-2-methoxyphenyl)propionic acid 2-(toluene-4-sulfonyl)ethyl ester (Intermediate 60, 4.7 g, 74%) as a light brown oil.

Provenance & Evidence