of catalytic amounts of piperidine over 4 A molecular sieves. Simply by changing reaction conditions (solvent and temperature) it is possible to control the stereochemical outcome of the reactions, obtaining pure (E)- and (Z)-nitro alkenes in high to excellent yields. The role of molecular sieves on the stereochemical control seems crucial in addition to that of piperidine, especially for the synthesis
在催化量的
哌啶存在下,脂族醛与硝基
烷烃在4 A
分子筛上反应。只需通过改变反应条件(溶剂和温度),就可以控制反应的立体
化学结果,从而以高到极好的收率获得纯的(E)-和(Z)-硝基烯烃。除
哌啶外,
分子筛在立体
化学控制中的作用似乎至关重要,特别是对于Z异构体的合成而言。