(8S,8aR)-8-(t-butyldimethylsilyloxy)-8,8a-dihydro-1H-oxazolo[3,4-a]pyridin-3(5H)-one

(6R,7R,8R,8aR)-8-(t-butyldimethylsilyloxy)-6,7-dihydroxy-tetrahydro-1H-oxazolo[3,4-a]pyridin-3(5H)-one

(3aR,7aR,8R,8aR)-8-(tert-Butyl-dimethyl-silanyloxy)-2,2-dimethyl-hexahydro-1,3,6-trioxa-4a-aza-s-indacen-5-one