Substrate-Induced Covalent Assembly of a Chemzyme and Crystallographic Characterization of a Chemzyme−Substrate Complex
摘要:
A substrate induced covalent assembly of a highly organized chemzyme known to be effective in both catalytic asymmetric aziridination and aza Diels-Alder reactions is described and the information gained from which led to an efficient one-pot aziridination protocol. The crystal structures of two chemzyme-iminium complexes were elucidated by X-ray diffraction analysis that provides critical insights into the binding of the substrates with the chemzyme.
Substrate-Induced Covalent Assembly of a Chemzyme and Crystallographic Characterization of a Chemzyme−Substrate Complex
摘要:
A substrate induced covalent assembly of a highly organized chemzyme known to be effective in both catalytic asymmetric aziridination and aza Diels-Alder reactions is described and the information gained from which led to an efficient one-pot aziridination protocol. The crystal structures of two chemzyme-iminium complexes were elucidated by X-ray diffraction analysis that provides critical insights into the binding of the substrates with the chemzyme.
Catalytic Asymmetric Synthesis of Trisubstituted Aziridines
作者:Li Huang、William D. Wulff
DOI:10.1021/ja203754p
日期:2011.6.15
is described which provides for the direct asymmetric catalytic synthesis of trisubstituted aziridines fromimines and diazo compounds. While unactivated imines were not reactive to α-diazo carbonyl compounds in which the diazo carbon was disubstituted, N-Boc imines react with both α-diazo esters and α-diazo-N-acyloxazolidinones to give trisubstituted aziridines with excellent diastereo- and enantioselectivities
Catalytic Asymmetric Aziridination of Benzhydryl Imines and Diazoacetate Esters with BOROX Catalysts from 3,3′-Disubstituted VANOL Ligands
作者:William D. Wulff、Yong Guan、Zhenjie Lu、Xiaopeng Yin、Aliakbar Mohammadlou、Richard J. Staples
DOI:10.1055/s-0039-1690860
日期:2020.7
into boroxinate catalysts that were used to screen the catalytic asymmetric aziridination of benzhydryl imines with ethyldiazoacetate. Each catalyst was screened in the reaction of imines generated from benzaldehyde and cyclohexanecarboxaldehyde and some with 4-nitro- and 4-methoxybenzaldehyde. In addition, the first report of the effect of the ester substituent of the diazoacetate ester on the asymmetric
Seeking Passe-Partout in the Catalytic Asymmetric Aziridination of Imines: Evolving Toward Substrate Generality for a Single Chemzyme
作者:Munmun Mukherjee、Anil K. Gupta、Zhenjie Lu、Yu Zhang、William D. Wulff
DOI:10.1021/jo101160c
日期:2010.8.20
The asymmetriccatalyticaziridination reaction (AZ reaction) of imines derived from dianisylmethyl (DAM) amine and tetra-methyldianisylmethyl (MEDAM) amine were examined with boroxinate catalysts preparedfrom both the VANOL and VAPOL ligands. This included an evaluation of different protocols for the preparation of the catalyst. The AZ reaction of DAM and MEDAM iminespreparedfrom nine different
衍生自亚胺的不对称催化反应氮杂环丙烷(AZ反应)d我一个nisyl米乙基(DAM)胺和四-我THYL d我一个nisyl米乙基(MEDAM)胺用由VANOL和VAPOL配体制备的硼恶烷酸酯催化剂检测。这包括对制备催化剂的不同方案的评估。检查了由9种不同的芳基和脂族醛制得的DAM和MEDAM亚胺的AZ反应。在AZ反应中,MEDAM亚胺优于DAM亚胺,具有更高的不对称诱导和更高的氮丙啶总产率。所述MEDAM亚胺发现也优于先前研究的二苯基甲基(二苯甲基或BH)和四-叔- BU TYL d我一个nisyl米乙基(BUDAM)亚胺,尤其适用于衍生自脂族醛的亚胺。在研究的九种不同的MEDAM亚胺上,平均不对称诱导率为VAPOL催化剂为ee的97%,VANOL催化剂为ee的96%。在所有情况下,除某些富电子芳基醛外,均可将MEDAM亚胺去保护成N -H氮丙啶。MEDAM亚胺比二苯甲基亚胺具有更高的反应性
How the Binding of Substrates to a Chiral Polyborate Counterion Governs Diastereoselection in an Aziridination Reaction: H-Bonds in Equipoise
作者:Mathew J. Vetticatt、Aman A. Desai、William D. Wulff
DOI:10.1021/ja103863j
日期:2010.9.29
stereochemistry-determining step of the self-assembled chiral Brønsted acid-catalyzed aziridination reactions of MEDAM imines and three representative diazo nucleophiles has been studied using ONIOM(B3LYP/6-31G*:AM1) calculations. The origin of cis selectivity in the reactions of ethyldiazoacetate and trans selectivity in reactions of N-phenyldiazoacetamide can be understood on the basis of the difference in specific
The iso-VAPOL ligand: synthesis, solid-state structure and its evaluation as a BOROX catalyst
作者:Anil K. Gupta、Xin Zhang、Richard J. Staples、William D. Wulff
DOI:10.1039/c4cy00742e
日期:——
and it is found that all three ligands have the cisoid conformations in the solid-state; the dihedral angle between the two aryl groups is less than 90°. In addition, all three ligands pack in the solid-state with no inter-molecular hydrogen bonds. This is the opposite to what has been reported for BINOL where all known structures exist with transoid conformations where the dihedral angle is >90° and
新的拱形联芳基配体iso-VAPOL是VAPOL的异构体,但具有VANOL的手性口袋。iso-VAPOL的合成涉及类似于VAPOL的环加成/电环化级联(CAEC),不同之处在于iso-VAPOL的起始原料成本不到其十分之一。确定了iso-VAPOL的固态结构以及VANOL的固态结构,因为以前没有报道过。将iso-VAPOL和VANOL的结构与VAPOL的已知固态结构进行了比较,发现所有三个配体在固态中均具有顺式构象。两个芳基之间的二面角小于90°。另外,所有三个配体都以固态堆积,没有分子间氢键。这与关于BINOL的报道相反,在BINOL中,所有已知的结构都存在具有反式构象的二面角> 90°,并且BINOL单元在相邻BINOL单元之间带有氢键。光谱证据包括给出的1 H和11 B NMR光谱表明,异VAPOL配体将以与B(OPh) 3形成BOROX催化剂的方式与以前通过光谱法和X射线晶体学报道