(R)-camphorsulfonic acid → tert-butyl 2-[(S)-7-(5-bromo-2-thienyl)-1,1-dioxoperhydro-1,4-thiazepin-7-yl]acetate.(1R)-10-camphorsulfonate

Participants

Reaction Steps

To a solution of tert-butyl 2-[7-(5-bromo-2-thienyl)-1,1-dioxoperhydro-1,4-thiazepin-7-yl]acetate (3.03 g) in ethanol (90 ml) was added (1R)-10-camphorsulfonic acid (912 mg) at 80° C. The clear solution was allowed to cool to room temperature with stirring for 2 hours to form crystalline solids. After being cooled on an ice bath for 30 minutes, the solids were collected and washed with ethanol to give tert-butyl 2-[(S)-7-(5-bromo-2-thienyl)-1,1-dioxoperhydro-1,4-thiazepin-7-yl]acetate•(1R)-10-camphorsulfonate (1.79 g, 91.6% ee) as a white solid.

Provenance & Evidence