Cationic Complexes of Palladium(II) and Platinum(II) as Lewis Acid Catalysts for the Diels−Alder Reaction
作者:Kristian Pignat、Jacopo Vallotto、Francesco Pinna、Giorgio Strukul
DOI:10.1021/om0003943
日期:2000.11.1
The synthesis of a series of Pd(II) and Pt(II) cationic complexes of the types [(P−P)M(solv)](Y)2, [(P−P)M(η2-Y)](Y), and [(P−P)M(μ-Cl)]2(Y)2 (where P−P = various diphosphines including chiral diphosphines (M = Pd, Pt; Y = TfO-, ClO4-, BF4-) is reported. All complexes are excellent catalysts for the Diels−Alder reaction between cyclopentadiene or cyclohexadiene and a number of simple dienophiles such
一系列的Pd(II)和Pt(II)的种类的阳离子络合物的合成[(P-P)M(SOLV)](Y)2,[(P-P)M(η 2 -Y)] (Y),和[(P-P)M(μ-Cl)的] 2(Y)2(其中,P-P =各种二膦包括手性二膦(M =钯,铂; Y = TFO -,CLO 4 - ,BF 4 -)被报告。所有的配合物都是环戊二烯或环己二烯与许多简单的双亲物如丙烯醛,甲基丙烯醛和甲基乙烯基酮之间的狄尔斯-阿尔德反应的极佳催化剂。在温和的条件下,在中等ee的条件下,手性二膦酸酯修饰的某些配合物可在Diels-Alder反应中充当对映选择性催化剂。在这方面的关键点是催化剂中仅存在一个空的配位点。