(R)-5-Oxo-1-((3aR,4R,7R,7aR)-2,2,7-trimethyl-tetrahydro-1,3,5-trioxa-6-aza-inden-4-yl)-pyrrolidine-2-carboxylic acid tert-butyl ester

(3aR,4S,6aS)-2,2,4-Trimethyl-tetrahydro-[1,3]dioxolo[4,5-c]pyrrole