2,2‘,5,5‘-Tetramethyl-4,4‘-bis(diphenylphoshino)-3,3‘-bithiophene: A New, Very Efficient, Easily Accessible, Chiral Biheteroaromatic Ligand for Homogeneous Stereoselective Catalysis
作者:Tiziana Benincori、Edoardo Cesarotti、Oreste Piccolo、Franco Sannicolò
DOI:10.1021/jo991533x
日期:2000.4.1
C2-symmetry chelating ligand for transition metals, is described, starting from 2,5-dimethylthiophene. The complexes of this electron-rich diphosphine with Ru(II) and Rh(I) were used as catalysts in some homogeneous hydrogenation reactions of prostereogenic carbonyl functions of alpha- and beta-ketoesters, of prostereogenic carbon-carbon double bonds of substituted acrylic acids, and of N-acetylenamino
对映纯(+)-和(-)-2,2',5,5'-四甲基-4,4'-双-(二苯基膦基)-3,3'-联噻吩(tetraMe-BITIOP的四步直接合成),描述了一种新的C2对称的过渡金属螯合配体,从2,5-二甲基噻吩开始。这种富电子的二膦与Ru(II)和Rh(I)的配合物在α-和β-酮酸酯的酯基羰基官能团,取代丙烯酸的酯基碳-碳双键的均相加氢反应中用作催化剂和N-乙酰基氨基酸。发现在所有实验中对映体过量都非常好,并且与文献报道的在相同实验条件下进行的相同反应的最佳结果相当,