A 3-(Z)-propenyl cephem compound is selectively prepared by reacting a phosphoranylidene cephem compound with acetaldehyde in the presence of a base in a solvent mixture comprising diethyl ether, formula (I), wherein R is a carboxyl protecting group; R
1
is hydrogen or R
2
CH
2
CO—; and R
2
is ethyl, 2-thiophenyl, phenyl, p-hydroxyphenyl or phenoxy.
在存在碱的情况下,将
磷酰亚胺头孢烯类化合物与
乙醛在包含
乙醚的溶剂混合物中反应,选择性地制备出3-(Z)-
丙烯基头孢烯类化合物,
化学式(I),其中R是羧基保护基;R1是氢或R2CH2CO-;R2是乙基、2-
噻吩基、苯基、对羟基苯基或苯氧基。