Selective Hydrogenation of Benzophenones to Benzhydrols. Asymmetric Synthesis of Unsymmetrical Diarylmethanols
摘要:
[GRAPHICS]trans-RuCl2[P(C6H4-4-CH3)(3)](2)(NH2CH2CH2NH2) acts as a highly effective precatalyst for the hydrogenation of a variety of benzophenone derivatives to benzhydrols that proceeds smoothly at 8 atm and 23-35 degrees C in 2-propanol containing t-C4H9OK with a substrate/catalyst ratio of 2000-20000. Use of a BINAP/chiral diamine Ru complex effects asymmetric hydrogenation of various ortho-substituted benzophenones and benzoylferrocene to chiral diarylmethanols with consistently high ee.
已经开发了一系列含有基于核苷的手性钳式配体的Mn I配合物,这些配合物具有模块化和可调的结构。该配合物在各种酮的氢化反应中显示出前所未有的高活性(高达9800 TON; TON =周转数),广泛的底物范围(81个实例),良好的官能团耐受性和出色的对映选择性(85-98%ee)。这些方面在稀土金属催化的氢化反应中很少见。该协议的实用性已在手性药物的多种关键中间体的不对称合成中得到证明。初步的机理研究表明,底物与催化剂相互作用的外层模式可能主导了催化作用。
Iron-catalyzed asymmetric hydrosilylation of ketones
作者:Ziqing Zuo、Lei Zhang、Xuebing Leng、Zheng Huang
DOI:10.1039/c5cc00612k
日期:——
iminopyridine-oxazoline (IPO) ligands have been synthesized. The most sterically hindered iron catalyst exhibits excellent activity (up to 99% yield) and high enantioselectivity (up to 93% ee) in asymmetrichydrosilylation of aryl ketones.
Fine tuning of molecular and supramolecular properties of simple trianglimines – the role of the functional group
作者:J. Gajewy、J. Szymkowiak、M. Kwit
DOI:10.1039/c6ra06095a
日期:——
affected by the nature and chirality of the dopant. The hexaimine macrocycles after reduction of the CN imine bonds formed trianglamines – useful chiral ligands in stereoselective synthesis. The Zn–trianglamine complexes were employed as catalysts for asymmetric hydrosilylation of prochiral ketones, providing products of enantiomeric excess up to 98%. This remains the best result obtained for Zn–diamine
New C2-symmetric tetrafluorobenzobarreleneligands were prepared and applied successfully to the rhodium-catalyzedasymmetric addition of arylboronic acids to aromatic aldehydes giving chiral diarylmethanols in high yield with high enantioselectivity.
Synthesis of the bifunctional BINOL ligands and their applications in the asymmetric additions to carbonyl compounds
作者:Ying-Chuan Qin、Lan Liu、Michal Sabat、Lin Pu
DOI:10.1016/j.tet.2006.06.049
日期:2006.10
the diphenylzinc addition which often require the addition of a significant amount of diethylzinc with cooling (or heating) the reaction mixture in order to achieve high enantioselectivity, using (S)-8 needs no additive and gives excellent results at room temperature. (S)-8 in combination with diethylzinc and Ti(OiPr)4 can catalyze the highly enantioselective phenylacetylene addition to aromatic aldehydes
分别从BINOL和H 8 BINOL与吗啉代甲醇的反应中开发了双功能BINOL和H 8 BINOL配体(S)-6和(S)-8的高效一步合成方法。这些化合物的X射线分析表明它们在结构上有相似之处和不同之处。双功能H 8 BINOL(S)-8已发现对二苯基锌与许多脂族和芳族醛的反应具有很高的对映选择性,尤其是对于线性脂族醛而言,对映选择性最强的催化剂。与开发用于添加二苯锌的其他催化剂不同,该催化剂通常需要在冷却(或加热)的同时添加大量的二乙基锌以实现高对映选择性,使用(S)-8无需添加剂,在室温下可获得优异的结果温度。(S)-8与二乙基锌和Ti(O i Pr)4结合可以催化高度对映选择性的苯乙炔加成芳族醛。尽管对映选择性还不是很高,但它在室温下还可以促进苯乙炔向苯乙酮的添加。在不使用Ti(O i Pr)4和路易斯碱添加剂的情况下,(S)-8与二乙基锌结合可以催化丙酸甲酯与醛的反应,形成高官能度
Catalytic enantioselective arylation of aldehydes: boronic acids as a suitable source of transferable aryl groups
作者:Antonio L. Braga、Diogo S. Lüdtke、Fabrício Vargas、Marcio W. Paixão
DOI:10.1039/b501485a
日期:——
The catalytic enantioselective arylation of several aldehydes using boronic acids as the source of transferable aryl groups is described; the reaction is found to proceed in excellent yields and high enantioselectivities (up to 97% ee) in the presence of a chiral amino alcohol.