Remote control of stereogenicity transfer by ring-generated anisotropic orbital overlap. Stereochemistry of hydrogen shift in the intramolecular reverse ene reaction of a cis-2-alkyl-1-alkenylcyclopropane
作者:Patti A. Parziale、Jerome A. Berson
DOI:10.1021/ja00012a032
日期:1991.6
Pyrolysis of 5 gave only 2-methyl-octa-2(Z),5(Z)-diene-1-d 3 -7(S)-d, with high stereospecificity at each of the three sites of sterogenicity. This result is the one predicted if the reaction is controlled by optimal overlap of the reacting C―H and π bond orbitals with the C s symmetric component of the degenerate 3E' highest occupied orbital of the cyclopropane ring
顺-2-(2-丙基)-1 (E)-丙烯基环丙烷在气相中在接近 230°C 的温度下发生热重排,活化参数为 E a =35.5±0.6 kcal/mol 和 log A = 12.05± 0.5 (A, s -1 )。合成了旋光同位素双标记类似物(cis-2(S)-(2(S)-propyl-1-d 3 )-1(S)-(1(E)-propenyl-2-d)cyclopropane 5)在 12 个步骤中从双环戊二烯中分离出来。5 的热解仅得到 2-methyl-octa-2(Z),5(Z)-diene-1-d 3 -7(S)-d,在三个位点中的每一个都具有高立体特异性如果反应受反应的 C-H 和 π 键轨道与环丙烷环的简并 3E' 最高占据轨道的 C s 对称分量的最佳重叠控制,则该结果是预测的结果