(1R,5S,6S,7R)-3,3-Ethylenedioxy-7-benzoyloxy-6-[(4S)-2-bromo-4-methyl-3-oxonon-1-en-6-ynyl]-bicyclo[3.3.0]octane 生成 (1'S,2'R,3'aR,6'aS)-1'-[(Z,3S,4S)-2-bromo-4-methyl-3-(oxan-2-yloxy)non-1-en-6-ynyl]-2'-(oxan-2-yloxy)spiro[1,3-dioxolane-2,5'-2,3,3a,4,6,6a-hexahydro-1H-pentalene]