Lau Samantha, Gasperini Danila, Webster Ruth L
Department of Chemistry, University of Bath, Claverton Down, Bath, UK.
Angew Chem Int Ed Engl. 2021 Jun 21;60(26):14272-14294. doi: 10.1002/anie.202010835. Epub 2021 Feb 25.
Transfer hydrogenation (TH) has historically been dominated by Meerwein-Ponndorf-Verley (MPV) reactions. However, with growing interest in amine-boranes, not least ammonia-borane (H N⋅BH ), as potential hydrogen storage materials, these compounds have also started to emerge as an alternative reagent in TH reactions. In this Review we discuss TH chemistry using H N⋅BH and their analogues (amine-boranes and metal amidoboranes) as sacrificial hydrogen donors. Three distinct pathways were considered: 1) classical TH, 2) nonclassical TH, and 3) hydrogenation. Simple experimental mechanistic probes can be employed to distinguish which pathway is operating and computational analysis can corroborate or discount mechanisms. We find that the pathway in operation can be perturbed by changing the temperature, solvent, amine-borane, or even the substrate used in the system, and subsequently assignment of the mechanism can become nontrivial.
传统上，转移氢化（TH）一直由梅耶尔温-庞多夫-韦利（MPV）反应主导。然而，随着人们对胺硼烷，尤其是氨硼烷（H₃N⋅BH₃）作为潜在储氢材料的兴趣日益浓厚，这些化合物也开始作为TH反应中的替代试剂出现。在本综述中，我们讨论了使用H₃N⋅BH₃及其类似物（胺硼烷和金属氨基硼烷）作为牺牲性氢供体的TH化学。我们考虑了三种不同的途径：1）经典TH，2）非经典TH，以及3）氢化。可以采用简单的实验机理探针来区分正在运行的是哪种途径，并且计算分析可以证实或否定这些机理。我们发现，通过改变系统中的温度、溶剂、胺硼烷，甚至所使用的底物，可以干扰正在运行的途径，随后机理的确定可能会变得很复杂。
