水相中银催化硝基化合物还原制备胺

Silver-catalyzed reduction of nitro to amines in water

芳胺是重要的基础化学品,被广泛应用于材料、药物化学等领域.发展新型、高效的催化合成策略制备芳香伯胺具有重要的科学研究意义.本文以商业易得的芳香硝基化合物为原料、廉价的三氟甲磺酸银为催化剂前体、苯硅烷为还原剂,在水相且温和条件下,实现了硝基的高选择性还原.该体系具有较好的兼容性,后处理操作简单,避免了氢气及高压釜设备,为芳香伯胺的制备提供了新的思路.机理研究表明,原位生成的银氢为活性物种,将硝基芳烃转化成为相应的芳香亚硝基化合物,中间体为偶氮苯及氢化偶氮苯.

Aromatic amines,an important basic chemical,are widely used in materials,medicinal chemistry and other fields.It is of great scientific significance to develop new and efficient catalytic synthesis strategies for the preparation of primary aromatic amines.In this study,the highly selective reduction of nitro was realized in the aqueous phase and under mild conditions by using commercial easily available aromatic nitro compound as raw material,cheap AgOTf as catalyst precursor,and phenylsilane as a reducing agent.The catalytic system with good compatibility,simple post-processing operation,and the avoidance of using the hydrogen and autoclave equipment,provided a new idea for the preparation of primary aromatic amines.The study on reaction mechanism showed that the silver hydrogen generated in situ was an active species,and the nitroaromatic compounds were converted into the corresponding nitrosoarenes,with azobenzene and hydrazobenzene as the intermediates.