Triethylamine → 5-Methanesulfonyloxymethyl-1,3-dihydro-isoindole-2-carboxylic acid benzyl ester

Participants

Reaction Steps

To a solution of 5-hydroxymethyl-1,3-dihydro-isoindole-2-carboxylic acid benzyl ester (65.75 g, 0.232 mol) in THF (470 mL) and EtOAc (770 mL) was added Et3N (39 mL, 0.28 mol). The solution was cooled in an ice-bath and a solution of methanesulphonyl chloride (19 mL, 0.245 mol) dissolved in EtOAc (50 mL) was added (so that the internal temp <12° C.). After stirring for 2 h in the ice-bath further additions of methanesulphonyl chloride (1.9 mL and 0.95 mL) and Et3N (3.9 mL) were made (so that by tlc there was no remaining starting material after a further 1 h of stirring). NaHCO3 (550 mL) was added and the solution stirred for 20 mins then saturated brine (200 mL) was added and the phases were separated. The organic phase was dried (MgSO4) and evaporated with seeding to give a damp solid which was used in the next step without thorough drying.

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