Mapping the Active Site in a Chemzyme: Diversity in the N-Substituent in the Catalytic Asymmetric Aziridination of Imines
摘要:
The active site of the aziridination catalyst derived from either the VANOL or VAPOL ligand and B(OPh)(3) is larger than expected and can accommodate not only significant substitution on the diarylmethyl unit of the imine but also that alkyl (but not perfluorylalkyl) substituents on the aryl groups lead to enhanced rates and enantioselection. The screen of diarylmethyl N-substituents on the imine revealed that the 3,5-di-tert-butyldianisylmethyl group (BUDAM) gave exceptionally high asymmetric inductions for imines of aryl aldehydes.
Mapping the Active Site in a Chemzyme: Diversity in the <i>N</i>-Substituent in the Catalytic Asymmetric Aziridination of Imines
作者:Yu Zhang、Zhenjie Lu、Aman Desai、William D. Wulff
DOI:10.1021/ol802431v
日期:2008.12.4
The active site of the aziridination catalyst derived from either the VANOL or VAPOL ligand and B(OPh)(3) is larger than expected and can accommodate not only significant substitution on the diarylmethyl unit of the imine but also that alkyl (but not perfluorylalkyl) substituents on the aryl groups lead to enhanced rates and enantioselection. The screen of diarylmethyl N-substituents on the imine revealed that the 3,5-di-tert-butyldianisylmethyl group (BUDAM) gave exceptionally high asymmetric inductions for imines of aryl aldehydes.
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