苯乙烯与4-氨基苯酚的氢氨甲基化反应研究北大核心CSCD

氢氨甲基化反应(HAM)是由简单烯烃、胺和合成气一锅法合成有价值胺的方法,具有较高的原子经济效率.然而,4-氨基苯酚作为一种特殊的反应底物,因其同时具有羟基和胺基官能团,在羰基化反应过程中能够选择性地在不同位点发生反应获得不同的产物.因此,我们系统研究了4-氨基苯酚与烯烃的HAM,通过筛选反应参数,确定了最优反应条件,并通过调控添加剂种类,选择性地在4-氨基苯酚的不同活性位点发生反应.结果表明,以甲醇为溶剂,三(3-甲氧基苯基)膦为配体,RhCl(PPh_(3))_(3)为催化剂前驱体,合成气压力4 MPa(H_(2)∶CO=3∶1),反应温度100℃,反应时间20 h时,该催化体系具有最高的反应活性.当以CH3COOH作为添加剂时,选择性的4-氨基苯酚的胺基官能团发生氢氨甲基化反应得到产物4-(2-苯丙基)氨基]苯酚,收率为82%;当以DBU作为添加剂时,得到苯乙酮产物,收率为92%.最后,提出了该反应可能的机理,为4-氨基苯酚的选择性反应提供理论依据.

The Hydroaminomethylation of Styrene with 4-Aminophenol

It is easy for hydroaminomethylation (HAM) to synthesize valuable amines from sample olefins, amines and syngas in one-pot and high atom economy. However, 4-Aminophenol, as a special reaction substrate owing to the presence of a phenolic hydroxyl group may show unexpected results in the HAM. Here, we firstly studied the HAM of 4-Aminophenol. By screening the reaction parameters, an efficient catalyst system was found as follows: methanol as a solvent, tris(3-methoxyphenyl)phosphine as a ligand, RhCl(PPh3)3 as a catalyst precursor, syngas pressure 4 MPa (H2 / CO = 3:1), 100 ?C, 20 hours. Interesting, when CH3COOH was used as an additive, the product 4-(2-phenylpropyl)amino]phenol of the HAM was obtained in the yield of 82%; When DBU was used as an additive, the product 2a that is acetophenone was obtained in the yield of 92%. Finally, the possible mechanism of this reaction was predicted.