利用两种特殊起始材料l-半胱氨酸和d-青霉胺的相反手性,合成了多种噻唑烷基氨基醇。l-半胱氨酸衍生物是比d-青霉胺更有效的手性诱导剂,在苯甲醛的对映选择性乙基化中ee高达92%。使用几种芳族、杂芳族和脂肪族醛评估了最佳催化剂的范围,提供了出色的 ( S )-对映选择性。鉴于l-半胱氨酸和d的相反手性-青霉胺噻唑烷,预期使用一种或另一种类型的衍生物作为配体将允许形成烷基化产物的相反构型。然而,虽然l-半胱氨酸噻唑烷主要产生 ( S ) 形式的烷基化产物,但d-青霉胺导致两种配置。当由两种类型的配体催化时,该反应的立体化学结果的显着差异促使我们研究这种结果背后的原因。进行了广泛的量子化学计算,以确定在这些类型的氨基醇存在下苯甲醛的对映选择性乙基化可以进行的过渡态结构。还探索了速率确定步骤的替代路径,并发现对实验结果的合理化具有决定性作用。据观察,配体的类型决定了手性产物形成的可及反应路径,这最终决定了两种可能构型之间的平衡。
Modular chiral thiazolidine catalysts in asymmetric aryl transfer reactions
摘要:
Modular chiral thiazolidine derivatives were synthesized in a single step from inexpensive and commercially available starting materials. These ligands catalyzed enantioselective arylation of different aldehydes using aryl boronic acids as a source of transferable aryl groups. The products were obtained in excellent yields and good enantioselectivities. (c) 2006 Elsevier Ltd. All rights reserved.
Novel thiazolidine derivatives as chiral catalysts in the enantioselective addition of diethylzinc to aldehydes
作者:Qinglin Meng、Yuelan Li、Yan He、Yedi Guan
DOI:10.1016/s0957-4166(00)00391-8
日期:2000.11
New chiral thiazolidine derivatives were synthesized conveniently from natural l-cysteine and showed good enantioselectivity (up to 90% ee) in the addition of diethylzinc to aldehydes. The catalytic efficiency of the thiazolidine derivatives is influenced by the different structures of the thiazolidine rings and the bulkiness of R moiety in the ester groups.
The steric effect and enantioselectivity of chiral 2,2-disubstituted thiaprolinol derivatives as ligands for borane reduction of aromatic ketones and for diethylzinc addition to aromatic aldehydes
作者:Hsiang-Ling Huang、Ya-Chuan Lin、Shyh-Fong Chen、Chia-Lin J. Wang、Lee Tai Liu
DOI:10.1016/0957-4166(96)00399-0
日期:1996.11
chiral amino alcohols 3a-e has been prepared from natural amino acid L-cysteine. These compounds have been used as chiral ligands for boranereduction of ketones and for diethylzinc addition to aldehydes. In the reduction of ketones, 3b-e have been used as the substitute of (R)-prolinol to provide (S)-alcohols in good yields and modest enantioselectivity (30–50% ee). In the diethylzinc addition to aldehydes
Modular chiral thiazolidine catalysts in asymmetric aryl transfer reactions
作者:Antonio Luiz Braga、Priscila Milani、Fabrício Vargas、Márcio W. Paixão、Jasquer A. Sehnem
DOI:10.1016/j.tetasy.2006.10.025
日期:2006.10
Modular chiral thiazolidine derivatives were synthesized in a single step from inexpensive and commercially available starting materials. These ligands catalyzed enantioselective arylation of different aldehydes using aryl boronic acids as a source of transferable aryl groups. The products were obtained in excellent yields and good enantioselectivities. (c) 2006 Elsevier Ltd. All rights reserved.
d-Penicillamine and l-cysteine derived thiazolidine catalysts: an efficient approach to both enantiomers of secondary alcohols
d-Penicillamine derived thiazolidine ligands were prepared in a two-step synthetic sequence and used in the enantioselective alkylation of a variety of aromatic aldehydes with diethylzinc at room temperature. Excellent ee, up to >99%, and nearly complete conversions were observed. Structurally analogous l-cysteine derived thiazolidine ligands were also synthesized and tested for comparative purposes
Deciphering the mechanism behind efficient enantioselective ethylation with thiazolidine‐based amino alcohols
作者:Nélia C. T. Tavares、Vanessa R. G. Cacho、Dora C. S. Costa、Sandra C. C. Nunes、Alberto A. C. C. Pais、Dina Murtinho、M. Elisa Silva Serra
DOI:10.1002/aoc.6567
日期:2022.3
difference in the stereochemical outcome of this reaction when catalyzed by the two types of ligands prompted us to investigate the reasons behind such results. Extensive quantum chemical calculations were performed in order to identify the transition state structures by which the enantioselective ethylation of benzaldehyde in the presence of these type of amino alcohols can proceed. An alternative path for
利用两种特殊起始材料l-半胱氨酸和d-青霉胺的相反手性,合成了多种噻唑烷基氨基醇。l-半胱氨酸衍生物是比d-青霉胺更有效的手性诱导剂,在苯甲醛的对映选择性乙基化中ee高达92%。使用几种芳族、杂芳族和脂肪族醛评估了最佳催化剂的范围,提供了出色的 ( S )-对映选择性。鉴于l-半胱氨酸和d的相反手性-青霉胺噻唑烷,预期使用一种或另一种类型的衍生物作为配体将允许形成烷基化产物的相反构型。然而,虽然l-半胱氨酸噻唑烷主要产生 ( S ) 形式的烷基化产物,但d-青霉胺导致两种配置。当由两种类型的配体催化时,该反应的立体化学结果的显着差异促使我们研究这种结果背后的原因。进行了广泛的量子化学计算,以确定在这些类型的氨基醇存在下苯甲醛的对映选择性乙基化可以进行的过渡态结构。还探索了速率确定步骤的替代路径,并发现对实验结果的合理化具有决定性作用。据观察,配体的类型决定了手性产物形成的可及反应路径,这最终决定了两种可能构型之间的平衡。