8-benzoyl-9-hydroxy-8-methoxy-3-methyl-4,6-dioxo-1-oxa-7-azaspiro<4.4>non-2-ene-2-carbaldehyde 、
乙氧甲酰基亚甲基三苯基膦 以
四氢呋喃 为溶剂,
以50%的产率得到ethyl (E)-3-[(5S,8S,9R)-8-benzoyl-9-hydroxy-8-methoxy-3-methyl-4,6-dioxo-1-oxa-7-azaspiro[4.4]non-2-en-2-yl]prop-2-enoate