Substituent effect of group 14 elements on the ring-opening reaction of cyclobutene
作者:Munehiro Hasegawa、Ippei Usui、Soichiro Konno、Masahiro Murakami
DOI:10.1039/c004972g
日期:——
group 14 elements at the 3-position were synthesized, and their thermal ring-opening reactions were studied. Carbon-substituted cyclobutene underwent the ring-opening reaction through an outward pathway to afford the E-diene exclusively. On the other hand, the ring-opening reaction of the silyl, germyl, and stannyl substituted cyclobutenes occurred in both outward and inward directions giving a mixture
合成了一系列在3位带有14族元素的环丁烯,并研究了它们的热开环反应。 碳取代的 环丁烯通过向外的途径进行开环反应,仅得到E-二烯。另一方面,甲硅烷基,癸基和苯乙烯基取代的环丁烯的开环反应在向外和向内均发生,得到E和Z异构体的混合物。计算的过渡态和总体分析的结构特征表明,Z异构体的形成可归因于HOMO与第14组元素的σ *轨道之间的供体/受体相互作用。有趣的是,内向偏好的顺序是硅 > 锡 > 通用电器。通过考虑能隙和σ *轨道与HOMO之间的重叠量,来解释甲硅烷基,癸基和苯乙烯基取代基的这些旋转行为。