(5R,7R,9S)-7-(Benzoyloxy)-9-bromo-2,2-dimethyl-1,3-dioxaspiro<4.5>decan-8-one

(S)-9-(2-Hydroxy-1-hydroxymethyl-ethylamino)-8-methoxy-2,2-dimethyl-1,3-dioxa-spiro[4.5]dec-8-en-7-one

(5S)-9-Azido-8-methoxy-2,2-dimethyl-1,3-dioxaspiro<4.5>dec-8-en-7-one

diethyl (S)-2-((8-methoxy-2,2-dimethyl-9-oxo-1,3-dioxaspiro[4.5]dec-7-en-7-yl)amino)malonate

(S)-8-methoxy-2,2-dimethyl-9-((triphenyl-5-phosphanylidene)amino)-1,3-dioxaspiro[4.5]dec-8-en-7-one