对位二取代环丁烷是否存在内消旋体?国内现行有机化学教材对此说法不一。如洪盈主编《有机化学》教材指出:“环丁烷中,当两个取代基处于对位时,无论它们是否相同,均无手性碳原子,只有顺反异构体,而没有旋光异构体。”而徐寿昌主编《有机化学》教材中认为:“1,3-环丁烷二羧酸只有顺式和反式两种异构体。”却又指出:“由于它们分子中都有 Is there a mesogen in the bis-substituted cyclobutane? There are different opinions on the current organic chemistry textbooks in China. As Hong Ying editor of “Organic Chemistry” textbook states: “Cyclobutane, when the two substituents in the position, regardless of whether they are the same, no chiral carbon atoms, only cis-trans isomers, and no optical rotation difference Structure. ”And Xu Shouchang editor of“ Organic Chemistry ”textbook that:“ 1,3-butane dicarboxylic acid only cis and trans two isomers. ”But also pointed out:" Because they have both molecules