由樟脑酸制备的胺衍生物用作合成相应铜 (I) 配合物的配体。分析了它们对双氧的反应性。在铜 (I) 配合物与 (1 R , 3 S )- N 1 , N 1 , N 3 , N 3反应期间,通过光谱观察到短寿命双(μ-氧化)铜配合物的形成-四甲基-1,2,2-三甲基环戊烷-1,3-二胺作为配体。此外,检测到配体系统的区域选择性去甲基化。配体甲基的氘化允许双(μ-氧化)铜配合物的结晶和表征。带有吡啶残基的配体衍生物会抑制相应的铜 (I) 配合物对分子氧的反应性。此外,可以对配体系统进行修饰,以用于与苯甲醛的分子内氧化反应,导致形成水杨醛,邻位选择性羟基化。
Novel tridentate ligands derived from (+)-camphoric acid for enantioselective ethylation of aromatic aldehydes
摘要:
Novel tridentate ligands were prepared from (+)-camphoric acid, using simple synthetic sequences. The synthesized ligands were used in enantioselective ethylations of benzaldehydes, showing enantioselectivities up to 92%, at room temperature. Extending the reaction to other aromatic aldehydes, very good results (almost quantitative yields and ee up to 97%, for m-anisaldehyde) were obtained. Structural features such as no substitution in the salicylaldehyde moiety of the Schiff base and an ethyl group in the nitrogen at the Cl position of the cyclopentane ring seem to be essential for obtaining high enantioselectivities. (C) 2015 Elsevier Ltd. All rights reserved.
Enantioselective ethylation of aldehydes with 1,3-N-donor ligands derived from (+)-camphoric acid
摘要:
Derivatives of (+)-camphoric acid were prepared by a short and simple synthetic sequence and proved to be excellent ligands for the enantioselective ethylation of benzaldellyde with diethylzinc, with ees of up to 96% being obtained The most efficient ligand was tested with several aromatic alclehydes and ees of up to 99% were observed Structural features of the ligands are determinant for achieving high enantioselectivities. (c) 2009 Elsevier Ltd All rights reserved