甲醇 、 (5
R)-6
c-chloro-2
c-methoxycarbonyl-3,3,4ξ-trimethyl-7-oxo-(5
rH)-4-thia-1-aza-bicyclo[3.2.0]heptanium; tetrafluoroborate 在
sodium carbonate 作用下,
生成
(S)-2-((E)-2-Chloro-2-methoxycarbonyl-vinylamino)-3-methyl-3-methylsulfanyl-butyric acid methyl ester