(E)-5-((2S,3aR,3''S,5R,5'R,6R,6''R,7aR)-2-(((tert-butyldiphenylsilyl)oxy)methyl)-6-methyl-3''-(((methylthio)carbonothioyl)oxy)-2,3,3a,3',3'',4',6,6'',7,7a-decahydrodispiro[furo[3,2-b]pyran-5,2'-furan-5',2''-pyran]-6''-yl)pent-4-en-1-yl pivalate