Carbocations as Lewis Acid Catalysts in Diels-Alder and Michael Addition Reactions
作者:Juho Bah、Johan Franzén
DOI:10.1002/chem.201304160
日期:2014.1.20
the carbocation as a highly powerful Lewis acid catalyst for organic reactions. The stable and easily available triphenylmethyl (trityl) cation was found to be a highly efficient catalyst for the Diels–Alder reaction for a range of substrates. Catalyst loadings as low as 500 ppm, excellent yields, and good endo/exo selectivities were achieved. Furthermore, by changing the electronic properties of the
通常,路易斯酸催化剂是基于金属的化合物,由于它们对低位的空轨道具有反应性。然而,碳阳离子是一种潜在的路易斯酸,已被忽略不计,它是一种催化剂。我们已经证明了碳正离子化作为有机反应的强力路易斯酸催化剂的潜力。稳定且容易获得的三苯甲基(三苯甲基)阳离子被发现是用于多种底物的Diels-Alder反应的高效催化剂。催化剂负载量低至500 ppm,优异的收率和良好的内/外达到了选择性。此外,通过改变三苯乙铵离子上取代基的电子性质,可以调节催化剂的路易斯酸度以控制反应的结果。该碳阳离子作为路易斯酸催化剂的能力也进一步扩展到迈克尔反应。