Domino Acylation/Diels–Alder Synthesis of <i>N</i>-Alkyl-octahydroisoquinolin-1-one-8-carboxylic Acids under Low-Solvent Conditions
作者:Stephen R. Slauson、Ryan Pemberton、Partha Ghosh、Dean J. Tantillo、Jeffrey Aubé
DOI:10.1021/acs.joc.5b00804
日期:2015.5.15
excellent yields. NMR monitoring suggested that the reaction proceeded via an initial acylation step followed by an intramolecular Diels–Alder reaction. For the latter step, a significant rate difference was observed depending on whether the amino group was substituted by a phenyl or an alkyl (usually benzyl) substituent, with the former noted by NMR to be substantially slower. The Diels–Alder step
描述了氨基乙基取代的二烯与马来酸酐之间的多米诺反应的发展,以提供N-取代的八氢异喹啉-1-酮。典型的步骤包括在低溶剂条件下,在0°C至室温下,用马来酸酐将1-氨基乙基取代的丁二烯处理20分钟,从而以中等至极好的收率得到一系列异喹啉酮羧酸。NMR监测表明,该反应通过最初的酰化步骤进行,随后进行了分子内Diels–Alder反应。对于后面的步骤,观察到明显的速率差异,具体取决于氨基是被苯基还是烷基(通常是苄基)取代基取代,而NMR指出前者要慢得多。通过密度泛函理论(DFT)方法研究了Diels–Alder步骤,得出的结论是,起始酰化中间体中的预组织程度对反应壁垒的影响最大。此外,电子对芳族环中的影响通过计算和实验研究了N-苯基底物。总体而言,与以前的方法相比,该协议通过消除微波批处理化学方法对该反应的要求以及显着减少溶剂的量,证明了其更易于扩展。