3-(2-Diazo-2-methoxycarbonyl-acetyl)-1,6-dimethyl-2-oxo-4-(2-vinyl-phenyl)-1,2,3,4-tetrahydro-pyrimidine-5-carboxylic acid ethyl ester 在
dirhodium tetraacetate 作用下,
以
苯 为溶剂,
生成 5-(2-ethenylphenyl)-6-ethoxycarbonyl-2-methoxycarbonyl-7,8-dimethyl-5H-[1,3]oxazolo[3,2-a]pyrimidin-4-ium-3-olate