Metal-catalyzed transferhydrogenation processes provide a widely-used alternative to direct hydrogenation processes of ketones. As part of an ongoing program, we report enantioselective C2-symmetric bis(phosphinite)–ruthenium(II) catalytic systems for the transferhydrogenation of prochiral aromatic ketones. The new catalytic systems can readily be formed under in situ conditions from C2-symmetric chiral bis(phosphinite)
金属催化的转移加氢工艺为酮的直接加氢工艺提供了广泛使用的替代方法。作为正在进行的计划的一部分,我们报告了对映体选择性C 2对称双(次膦酸酯)-钌(II)催化体系,用于转移前手性芳族酮的氢化作用。新的催化体系可以容易地形成下原位条件从Ç 2 -对称的手性双(膦酸酯)的配体和的[Ru(η 6 - p -cymene)(μ-Cl)的CL] 2在转移氢化反应介质。这些手性钌催化剂体系可作为苯乙酮衍生物不对称转移加氢的催化剂前体。异-PrOH,得到相应的光学活性仲醇,其ee最高可达94%。
New C 2 -symmetric six-membered carbene ligands incorporating two hydroxyl groups for palladium-catalyzed deprotonative-cross-coupling processes (DCCP) of sp 3 C–H bonds in diarylmethanes
作者:Bi-Hui Zhou、Chen Wu、Xing-Xiu Chen、Hong-Xia Huang、Lin-Lin Li、Li-Mei Fan、Jie Li
DOI:10.1016/j.tetlet.2017.09.022
日期:2017.11
N-heterocyclic carbene, were synthesized in high yields using a two-step procedure starting from commercially available amino alcohols. In situ prepared corresponding carbenes were tested in palladium-catalyzed C(sp3)−H arylation of 4-benzylpyridine with aryl bromides, affording triarylmethane derivatives in high yields.
A series of chiral, C2 symmetric tridentate N‐heterocyclic carbene precursors, containing two N‐functionalized hydroxyl or alkoxyl groups, were synthesized. They were applied to catalyze the asymmetric conjugate addition of diethylzinc to cyclohex‐2‐enone and cyclopent‐2‐enone. Enantioselectivity of corresponding reactions can be accomplished with up to 76% ee, and 65% ee, respectively. Flip of major
New enantiopure imidazolinium carbene ligands incorporating two hydroxy groups for Lewis acid-catalyzed diethyl zinc addition to aldehydes
作者:Mazhar Gilani、René Wilhelm
DOI:10.1016/j.tetasy.2008.10.011
日期:2008.10
New enantiopure imidazolinium Carbene ligands incorporating two hydroxy functions have been synthesized from commercially available chiral amino alcohols and diamines. These ligands in combination with different metallic salts have been investigated in the diethylzinc addition to aldehydes with good yields and enantioselectivity. (C) 2008 Elsevier Ltd. All rights reserved.
Vannoorcnberghe, Yves; Buono, Gerard, Journal of the American Chemical Society, 1990, vol. 112, # 16, p. 6142 - 6143