(S)-2,2-Bis(trifluormethyl)-4-(3-diazo-2-oxopropyl)-1,3-oxazolidin-5-on

(S)-3,3-bis(trifluoromethyl)dihydropyrrolo[1,2-c]oxazole-1,6(3H,5H)-dione

5-triphenylmethyl-2-oxa-5-aza-bicyclo(2.2.1)heptan-3-one

trans-N-trityl-4-hydroxy-L-proline

(1S,4S)-3-(R/S)-methoxy-2-oxa-5-aza-bicyclo[2.2.1]heptane