alanine derived systems were determined by X-ray analyses, and in all cases, the three phenolate arms point up with respect to the central methine. Alkali metal binding studies (Li, Na, K, Rb, and Cs) were carried out for the dimethylamine, benzylamine, and glycine compounds 5−7, and these compounds were found to have some selectivity for potassium cations. NMRstudies demonstrate that C3 symmetry is retained
一系列 C3 对称三(3,5-二烷基-2-羟基苯基)甲烷(烷基 = 叔丁基、甲基、叔戊基)已从各自的酚类中以高产率合成并得到充分表征,包括单晶 X -射线结构的两个例子。二叔丁基取代的化合物 1a 已衍生为三酰氯 4,然后用各种胺(二甲胺、苄胺、甘氨酸和丙氨酸)处理,从中得到相应的三酰胺 5形成了-8个。二甲胺、甘氨酸和丙氨酸衍生系统的绝对几何和构象通过 X 射线分析确定,并且在所有情况下,三个酚盐臂相对于中心次甲基指向上方。对二甲胺、苄胺和甘氨酸化合物 5-7 进行了碱金属结合研究(Li、Na、K、Rb 和 Cs),并且发现这些化合物对钾阳离子具有一定的选择性。核磁共振研究表明,所有化合物都保留了 C3 对称性,锂离子络合的化学计量比为 1:1,而络合钠阳离子需要两个配体。还测定了具有苦味酸锂的二甲胺衍生物和具有四苯基硼酸钠的苄胺和甘氨酸衍生物的晶体结构。
Assembling a Hybrid Pd Catalyst from a Chiral Anionic Co
<sup>III</sup>
Complex and Ligand for Asymmetric C(sp
<sup>3</sup>
)–H Functionalization
作者:Hua‐Jie Jiang、Xiu‐Mei Zhong、Jie Yu、Ying Zhang、Xinhao Zhang、Yun‐Dong Wu、Liu‐Zhu Gong
DOI:10.1002/anie.201812426
日期:2019.2.4
An unusual hybrid palladiumcatalyst containing an anionic chiral CoIII complex and a chiral phosphoramidite ligand shows a high capacity for catalyzing asymmetric thioamide‐directed C(sp3)−H arylation and delivers excellent yield and enantioselectivity (up to 99 % yield, 99 % ee). Significant synergy between the chiral ligand and the anion in terms of stereochemical control was observed. Mechanistic
Sterically hindered, regenerable Schiff base complexes, solutions
申请人:Bend Research, Inc.
公开号:US05266283A1
公开(公告)日:1993-11-30
There are disclosed saltmen-type metallo Schiff base complexes and oxygen-sorbing and -desorbing solutions of the same, pressure- and temperature-swing oxygen separation processes using the complexes and solutions, and methods of regenerating such complexes and solutions.
Tertiary Pentyl Groups Enhance Salen Titanium Catalyst for Highly Enantioselective Trimethylsilylcyanation of Aldehydes
作者:Sidney Liang、Xiu R. Bu
DOI:10.1021/jo0161779
日期:2002.4.1
recognized to be highly effective steric groups that can enhance enantioselectivity of salen titanium complexes when they are used in asymmetrical cyanation of aromatic aldehydes. High ee (92-97%) has been obtained with several aldehyde substrates. Compared to its tert-butyl analogue, the tert-pentyl group has been found to improve enantioselectivity and in some cases quite dramatically.
叔戊基被认为是高效的立体基团,当它们用于芳族醛的不对称氰化时,可以提高salen钛配合物的对映选择性。使用几种醛底物已获得高 ee (92-97%)。与其叔丁基类似物相比,已发现叔戊基可提高对映选择性,并且在某些情况下相当显着。
Unsymmetric chiral salen Schiff bases: A new chiral ligand pool from bis-schiff bases containing two different salicylaldehyde units
作者:Jose Lopez、Sidney Liang、Xiu R. Bu
DOI:10.1016/s0040-4039(98)00784-9
日期:1998.6
An efficient and facile synthesis of a new class of novel chiral Salen Schiff base ligands has been developed via a stepwise approach. An important feature of these new Salen ligands is that they possess two different salicylaldehyde units, therefore, while steric factor or electronic factor can be fixed on one side, electronic or/and steric factors can be tuned from the other side with different substituents. (C) 1998 Elsevier Science Ltd. All rights reserved.