作者:Olivier Pilet、Pierre Vogel
DOI:10.1002/hlca.19810640812
日期:1981.12.16
addition of TCNE to 7 yielding the bis-adduct 9. Similar reactivity trends were observed for the additions of TCNE to the less reactive 2,3,5,6-tetramethylidene-7-oxanorbornane (2). The following second order rate constants (toluene, 25°) and activation parameters were obtained for: 1 + TCNE 7: k1 = (255 + 5) 10−4 mol−1 · s−1, ΔH≠ = (12.2 ± 0.5) kcal/mol, ΔS≠ = (−24.8 ± 1.6) eu.; 7 + TCNE 9, k2 = (0.7 ± 0
Pd催化的环戊二烯与顺丁烯二酸酐的Diels-Alder加合物的双碳甲氧基化反应制得甲基降冰片烷-2,3-内基-5,6-外基-四羧酸酯(4),将其分三步转化为2,3, 5,6-四甲基-异降冰片烷(1)。四氰基乙烯(TCNE)与1的环加成反应生成相应的单加合物7的速度(甲苯,25°)比TCNE与7生成双加合物9的反应快364倍。在反应性较低的2,3,5,6-四亚甲基-7-氧杂硼烷中添加TCNE观察到类似的反应趋势(2)。获得以下二阶速率常数(甲苯,25°)和以下活化参数:1 + TCNE 7:k 1 =(255 + 5)10 -4 mol -1 ·s -1,ΔH ≠=(12.2± 0.5)kcal / mol,ΔS ≠=(-24.8±1.6)eu .; 7 + TCNE 9,k 2=(0.7±0.02)10 -4 mol -1 ·s -1,ΔH ≠=(14.1±1.0)kcal / mol,ΔS