Reductions by deuterium over Pd/C were carried out on a series of dihydrofuran compounds. A stereoselective cis hydrogenation is observed in all cases. The stereochemistry of the dideuteriated products was determined by NOE measurements. According to the steric hindrance of the substituents, deuterium entry is found on the α face or the β face of dihydrofuran ring. The formation of mono- or trideuteriated
在一系列二氢
呋喃化合物上,
氘在Pd / C上的还原反应。在所有情况下均观察到立体选择性顺式氢化。通过NOE测量确定经过重新配制的产品的立体
化学。根据取代基的空间位阻,
氘进入二氢
呋喃环的α面或β面。单或三
氘代产物的形成可能是由吸附的
氢化物和半
氢化物之间的交换反应引起的。在C4处观察到了意外的逆向动力学同位素效应,表明溶解在
金属晶格中的原子氢的振动能非常低。