(3aR,5S,5'S,6S,6aR)-5-((R)-2,2-dimethyl-1,3-dioxolan-4-yl)-2,2,5'-trimethyldihydro-5H-spiro[furo[2,3-d][1,3]dioxole-6,4'-oxazolidin]-2'-one

(3aR,5S,5'S,6S,6aR)-3'-benzyl-5-((R)-2,2-dimethyl-1,3-dioxolan-4-yl)-2,2,5'-trimethyldihydro-5H-spiro[furo[2,3-d][1,3]dioxole-6,4'-oxazolidin]-2'-one

N-[(3aR,5S,6S,6aR)-6-Acetyl-5-((R)-2,2-dimethyl-[1,3]dioxolan-4-yl)-2,2-dimethyl-tetrahydro-furo[2,3-d][1,3]dioxol-6-yl]-2,2,2-trichloro-acetamide

2,2,2-Trichloro-N-[(3aR,5S,6S,6aR)-5-((R)-2,2-dimethyl-[1,3]dioxolan-4-yl)-2,2-dimethyl-6-vinyl-tetrahydro-furo[2,3-d][1,3]dioxol-6-yl]-acetamide

2,2,2-Trichloro-N-[(3aR,5S,6S,6aR)-5-((R)-2,2-dimethyl-[1,3]dioxolan-4-yl)-6-((S)-1-hydroxy-ethyl)-2,2-dimethyl-tetrahydro-furo[2,3-d][1,3]dioxol-6-yl]-acetamide