(1S,2S,5R,6S)-ethyl 2-spirohydantoin-bicyclo[3.1.0]hexane-6-carboxylate

(3a'R,3b'R,4'S,4a'S,5a'R)-ethyl 5'-oxohexahydrospiro[cyclohexane-1,2'-cyclopropa[3,4]cyclopenta[1,2-d][1,3]dioxole]-4'-carboxylate

dimethyl (3a'R,3b'R,4'R,4a'S,5'R,5a'S)-5'-aminohexahydrospiro[cyclohexane-1,2'-cyclopropa[3,4]cyclopenta[1,2-d][1,3]dioxole]-4',5'-dicarboxylate

dimethyl (3a'R,3b'R,4'R,4a'S,5'R,5a'S)-5'-azidohexahydrospiro[cyclohexane-1,2'-cyclopropa[3,4]cyclopenta[1,2-d][1,3]dioxole]-4',5'-dicarboxylate

ethyl (3a'R,3b'R,4'S,4a'S,5'S,5a'R)-5'-hydroxy-5'-(trichloromethyl)hexahydrospiro[cyclohexane-1,2'-cyclopropa[3,4]cyclopenta[1,2-d][1,3]dioxole]-4'-carboxylate