(3aR,6S,7S,7aR)-7-((tert-butyldimethylsilyl)oxy)-2',2'-dimethyltetrahydrospiro[pyrano[3,4-d]oxazole-6,4'-[1,3]dioxolan]-2(3H)-one

(3aR,6S,7S,7aR)-7-hydroxy-2',2',3-trimethyltetrahydrospiro[pyrano[3,4-d]oxazole-6,4'-[1,3]dioxolan]-2(3H)-one

(2S)-2',2'-dimethyl-2H-pyran-2-spiro-4'-(1',3'-dioxolan)-3(6H)-one

tert-Butyl-((5S,10S)-2,2-dimethyl-1,3,6-trioxa-spiro[4.5]dec-8-en-10-yloxy)-dimethyl-silane

(3aR,6S,7S,7aR)-3-benzyl-7-hydroxy-2',2'-dimethyltetrahydrospiro[pyrano[3,4-d]oxazole-6,4'-[1,3]dioxolan]-2(3H)-one