Calow Adam D J, Carbó Jorge J, Cid Jessica, Fernández Elena, Whiting Andrew
Centre for Sustainable Chemical Processes, Department of Chemistry, Science Laboratories, Durham University , South Road, Durham DH1 3LE, U.K.
J Org Chem. 2014 Jun 6;79(11):5163-72. doi: 10.1021/jo5007366. Epub 2014 May 14.
A combination of in situ IR spectroscopy (ReactIR) and DFT calculations have been used to understand what factors govern the selectivity in the addition of primary amines to α,β-unsaturated aldehydes and ketones, i.e., 1,2- versus 1,4-addition. It has been found that the 1,2-addition products (α,β-unsaturated imines following addition and elimination) usually predominate for most systems. However, exceptions, such as methyl vinyl ketone, selectively give 1,4-addition products. This has been rationalized by DFT calculations that show that major conformational effects are involved, controlled mainly by steric effects of carbonyl substituents, resulting in a model that provides simple and predictable preparation of α,β-unsaturated imines for in situ utilization in synthesis.
原位红外光谱（ReactIR）和密度泛函理论（DFT）计算相结合，用于理解在伯胺加成到α,β-不饱和醛和酮（即1,2-加成与1,4-加成）过程中，哪些因素决定了选择性。研究发现，对于大多数体系，1,2-加成产物（加成和消除后得到α,β-不饱和亚胺）通常占主导。然而，也有一些例外情况，如甲基乙烯基酮，会选择性地生成1,4-加成产物。DFT计算对此进行了合理的解释，结果表明主要涉及主要构象效应，主要受羰基取代基的空间效应控制，从而得到了一个模型，该模型可为合成中原位利用α,β-不饱和亚胺提供简单且可预测的制备方法。
