作者:Stefania F. Musolino、O. Stephen Ojo、Nicholas J. Westwood、James E. Taylor、Andrew D. Smith
DOI:10.1002/chem.201604788
日期:2016.12.23
The non‐enzymatic acylative kineticresolution of challenging aryl–alkenyl (sp2 vs. sp2) substituted secondaryalcohols is described, with effective enantiodiscrimination achieved using the isothiourea organocatalyst HyperBTM (1 mol %) and isobutyric anhydride. The kineticresolution of a wide range of aryl–alkenyl substituted alcohols has been evaluated, with either electron‐rich or naphthyl aryl
描述了具有挑战性的芳基-烯基(sp 2与 sp 2 )取代的仲醇的非酶酰化动力学拆分,并使用异硫脲有机催化剂 HyperBTM(1 mol%)和异丁酸酐实现了有效的对映区分。已经评估了各种芳基-烯基取代醇的动力学拆分,其中富电子或萘基芳基取代基与未取代的乙烯基取代基相结合,提供了最高的选择性( S =2-1980)。演示了使用该方案对模型芳基-乙烯基(sp 2与 sp 2 )取代的仲醇进行克级(2.5 g)动力学拆分,可获取每种产物对映体的 >1 g 99:1呃。
<b>PQXdpap</b>: Helical Poly(quinoxaline-2,3-diyl)s Bearing 4-(Dipropylamino)pyridin-3-yl Pendants as Chirality-Switchable Nucleophilic Catalysts for the Kinetic Resolution of Secondary Alcohols
Helically chiral poly(quinoxaline-2,3-diyl)s bearing 4-(dipropylamino)pyridin-3-yl pendants at the 5-position of the quinoxaline ring (PQXdpap) exhibited high catalytic activities and moderate to high selectivities (up to s = 87) in the acylative kinetic resolution of secondary alcohols. The solvent-dependent helical chirality switching of PQXdpap between pure toluene and a 1:1 mixture of toluene and
highly reactive RMgBr reagents were effectively deactivated by bis[2-(N,N-dimethylamino)ethyl] ether and then were employed in the highly enantioselective addition of Grignardreagents to aldehydes. The reaction was catalyzed by the complex of commercially available (S)-BINOL and Ti(Oi-Pr)4 under mild conditions. Compared with the other observed Grignardreagents, alkyl Grignardreagents showed higher enantioselectivity
Catalytic Highly Enantioselective Alkylation of Aldehydes with Deactivated Grignard Reagents and Synthesis of Bioactive Intermediate Secondary Arylpropanols
作者:Yi Liu、Chao-Shan Da、Sheng-Li Yu、Xiao-Gang Yin、Jun-Rui Wang、Xin-Yuan Fan、Wei-Ping Li、Rui Wang
DOI:10.1021/jo101351t
日期:2010.10.15
of the high reactivity of Grignard reagents, a direct, highly enantioselective Grignard reaction with aldehydes has rarely been disclosed. In this report, Grignard reagents were introduced with bis[2-(N,N′-dimethylamino)ethyl] ether (BDMAEE) to effectively deactivate their reactivity; thus, a highly enantioselective alkylation of aldehydes with Grignard reagents resulted from catalysis by (S)-BINOL-Ti(OiPr)2
由于格氏试剂的高反应性,很少公开与醛类直接,高度对映选择性的格氏试剂反应。在该报告中,格氏试剂与双[2-(N,N'-二甲基氨基)乙基]醚(BDMAEE)一起引入,以有效地使其活性失活。因此,由(S)-BINOL-Ti(O i Pr)2催化导致格氏试剂对醛的高度对映选择性烷基化。认为BDMAEE螯合了RMgBr的Schlenk平衡的原位生成的盐MgBr 2和RMgBr与Ti(O i Pr)4的重金属化产生的Mg(O i Pr)Br的螯合作用。镁盐可以积极地促进不希望有的背景反应,生成外消旋体。该螯合作用无疑抑制了Mg盐的催化活性,抑制了不需要的背景反应,并且使得能够被(S)-BINOL-Ti(O i Pr)2催化的高对映选择性加成。因此,与以前的研究相比,没有除去Mg盐的副产物,使用了比RMgBr少的Ti(O i Pr)4,并且在该催化不对称反应中避免了极低的温度。各种烷基格氏试剂中的不对称
Chiral phosphonite, phosphite and phosphoramidite η6-arene-ruthenium(ii) complexes: application to the kinetic resolution of allylic alcohols
作者:Mariano A. Fernández-Zúmel、Beatriz Lastra-Barreira、Marcus Scheele、Josefina Díez、Pascale Crochet、José Gimeno
DOI:10.1039/c0dt00140f
日期:——
[RuCl2(η6-arene)(R)-PR(binaphthoxy)}] (arene = benzene (1), p-cymene (2), mesitylene (3); R = Ph (a), OPh (b), piperidyl (c)) are described. Derivatives 1–3 have been employed to promote the kinetic resolution of allylic alcohols through a redox-isomerization process. As a general trend, the best selectivities are attained with the more sterically hindered catalysts i.e. those containing p-cymene or mesitylene ligands