The ?-Anisotropy of the Double Bond of asyn-11-Oxasesquinorbornene Derivative.. Stereoselectivity of theDiels-Alder additions of (2-norborneno)[c]furan. Crystal structure of 11-oxa-endo-tetracyclo[6.2.1.13,6.02,7]-dodec-2(7)-ene-9,10-exo-dicarboxylic anhydride
作者:Jean-Pierre Hagenbuch、Pierre Vogel、A. Alan Pinkerton、Dieter Schwarzenbach
DOI:10.1002/hlca.19810640613
日期:1981.9.23
was established by single-crystal X-ray diffraction. A dihedral angle of 163° was measured between the C(1,2,7,8) and C(2,3,6,7) planes in 5. This important deviation from planarity for the C(2,7) double bond is attributed to (π, ω)-repulsive interactions that make the π-electron density of 2-norbornene and 7-oxa-2-norbornene derivatives preferentially polarized toward the exo-face. This finding is discussed
(2-降冰片基)[ c ]呋喃(4)与马来酸酐的反应得到11-氧杂-内-四环[6.2.1.1 3,6 .0 2,7 ] dodec-2(7)-ene-9, 10-外-二酐(5),并与甲基乙炔,甲基-11-氧杂内-tetracyclo [6.2.1.1 3,6 0.0 2,7 ]十二-2(7),9-二烯-9,10- -二羧酸盐(7)。该SYN -11氧杂sesquinorbornenes 5和7可以与他们进行cycloaddents平衡。它们比相应的抗氧化剂至少稳定2 kcal / mol-sesquinorbornenes 6和8。的结构7从它的光谱数据推断,通过环氧化用空气或过酸,得到外-epoxide 13和通过催化氢化,得到14。通过单晶X射线衍射确定5的结构。在5中的C(1,2,7,8)和C(2,3,6,7)平面之间测得163°的二面角。C(2,7)双键与平面度的重要偏离归因于(π