The relative configuration of the carbons bearing the ester groups in the cycloadducts of anhydro - 4- hydroxythiazolium hydroxides with dimethyl maleate and dimethylfumarate is revised in the light of an X-ray crystallographic analysis. Steric effects are considered to account for the preferred exo approach of the dipole and the dipoiarophile.
根据X射线晶体学分析,修改了在
脱水-
4-羟基
噻唑鎓
氢氧化物与
马来酸二甲酯和
富马酸二甲酯的环加合物中带有
酯基的
碳的相对构型。立体效应被认为是偶极子和亲双油菌的首选外向方法。