14 族元素 Si --> Pb 的降
冰片基阳离子已从取代的 3-
环戊烯甲基前体通过将瞬时阳离子分子内加成到 3-
环戊烯甲基取代基的 C=C 双键(pi-路线到降
冰片基阳离子)合成。降
冰片基阳离子 4a (E = Si, R = Me), 4e (E = Si, R = Et), 4f (E = Si, R = Bu), 4g (E = Ge, R = Bu), 4h (E = Sn, R = Bu) 和 4i (E = Pb, R = Et) 已通过其特征 NMR
化学位移 (4a,e,f, delta((29)Si) = 80-87, delta((( 13)C)(CH=) = 149.6-150.6; 4g, delta((13)C)(CH=) = 144.8; 4h, delta((119)Sn) = 334, delta((13)C)(CH =) = 141.5; 4i, delta((207)Pb)