O,O'-双(2,2,2-三氟乙基)磷乙酸甲酯 、
(5S,6S)-6-Methoxy-5-p-tolylsulfanyl-dihydro-pyran-3-one 在
K-hexamethyldisilazide 作用下,
生成 [(5R,6R)-6-Methoxy-5-p-tolylsulfanyl-dihydro-pyran-(3E)-ylidene]-acetic acid methyl ester 、 [(5R,6R)-6-Methoxy-5-p-tolylsulfanyl-dihydro-pyran-(3Z)-ylidene]-acetic acid methyl ester