Synthesis, Spectroscopic, and Structural Properties of Spirocyclopropanated Bicyclobutylidenes and Their Radical Cations
作者:Armin de Meijere、Horst Wenck、Stephan Zöllner、Pascal Merstetter、Anton Arnold、Fabian Gerson、Peter R. Schreiner、Roland Boese、Dieter Bläser、Rolf Gleiter、Sergei I. Kozhushkov
increasing nucleophilicity of the double bonds in the order 1 < 4 < 3 < 5. Following the radical cations of the three symmetrical bicyclobutylidenes without (2a, b) and with six (5) spiroannelated cyclopropane rings, the radical cations of two symmetrical bicyclobutylidenes with two (4) and four (3) such rings were studied by ESR spectroscopy. Whereas 2b.+, 3.+, and 5.+ could be generated by electrolytic
螺环丙烷化的双环丁烯基3-7是通过相应螺环丙烷化的环丁酮(3和5)的McMurry偶联,Staudinger-Pfenniger反应(4),Wittig内酯的氧化偶联(4)或全螺环丙烷化的环丁酮的Wittig烯化反应制备的(6和7) )。母体2a和全螺环丙烷化的双环丁烯5的结构通过X射线晶体学测定,该X射线晶体学揭示了双键周围相当大的空间拥挤。结果5确实进行了二氯卡宾的添加,间氯过苯甲酸的环氧化和CH 2 I 2 / ZnEt 2的环丙烷化,但是没有添加更大体积的二溴卡宾。5与四氰基乙烯的反应进展顺利,但导致一个内部环丙烷环之一的近端单键上形成了一个正式的[3 + 2]环加合物。对于每对β-和α-螺环丙烷基团,双环丁烯的连续螺环丙烷化分别导致12和17nm的紫外光谱发生红移。在这些双环丁烯的He(I)-光电子能谱中,发现螺环丙烷化对其pi电离能(pi-IE,)的影响几乎是加和的,导致每增加一个β-螺环丙烷降低0