ethyl (E)-4-((3a'S,4'S,7'S,7a'R)-7'-(2-((tert-butyldiphenylsilyl)oxy)ethyl)tetrahydro-4'H-spiro[cyclohexane-1,2'-[1,3]dioxolo[4,5-c]pyran]-4'-yl)-3-methylbut-2-enoate