4-Toluenesulfonyl chloride → (cis)-1-Benzoyl-4-tosyloxy-L-proline, methyl ester

Participants

Reaction Steps

A solution of (cis)-1-benzoyl-4-hydroxy-L-proline, methyl ester (1.9 g, 7.63 mmole) in pyridine (6 ml) was stirred under argon and treated with p-toluenesulfonyl chloride (1.75 g, 9.16 mmole). The reaction was stirred overnight, treated with additional p-toluenesulfonyl chloride (0.145 g, 0.76 mmole) and stirred for 24 hours. Ice water was added followed by ethyl acetate. The organic layer was washed with 1N HCl, brine, and dried. Filtration and concentration in vacuo afforded the title compound as a foam which was used without purification in the subsequent step.

Provenance & Evidence