Controlling cis/trans-selectivity in intramolecular Diels–Alder reactions of benzo-tethered, ester linked 1,3,9-decatrienes
作者:Emma L. Pearson、Anthony C. Willis、Michael S. Sherburn、Michael N. Paddon-Row
DOI:10.1039/b716910h
日期:——
Predictions from DFT (B3LYP/6-31 G(d))-computed stereoisomer product distributions for intramolecular Diels-Alder (IMDA) reactions have been successfully replicated in the laboratory. Benzo-tethered hexadienyl acrylates generally undergo moderately trans-selective IMDA reactions which, as suggested by DFT calculation, arise from two opposing transition structure (TS) features: stabilising secondary
DFT(B3LYP / 6-31 G(d))计算的分子内Diels-Alder(IMDA)反应立体异构体产物分布的预测已在实验室中成功复制。DFT计算表明,苯甲酸酯系丙烯酸己二烯基丙烯酸酯通常会发生中等程度的反选择性IMDA反应,这是由两个相对的过渡结构(TS)特征引起的:稳定次要轨道相互作用(在顺式TS中更强)和稳定pi-苯并部分和1,3-二烯组分之间的共轭相互作用-在反式TS中更强。预计通过反式-TS的空间不稳定,在二烯的C3或芳环的C12上带有可除去取代基(即Br或TMS)的底物会发生高度顺式选择性IMDA反应。预计在C3和C12之间带有两个原子链的底物会通过使顺式TS不稳定而经历高度反式选择性的分子内环加成反应。这些计算是通过实验证明的。