methanesulfonic acid 3,3,6,6-tetramethyl-4-oxo-5-trimethylsilanyl-bicyclo[3.1.0]hex-2-yl ester

2,4,6-triisopropyl-benzenesulfonic acid 3,3,6,6-tetramethyl-4-oxo-bicyclo[3.1.0]hex-2-yl ester