The Asymmetric Aza-Claisen Rearrangement: Development of Widely Applicable Pentaphenylferrocenyl Palladacycle Catalysts
作者:Daniel F. Fischer、Assem Barakat、Zhuo-qun Xin、Matthias E. Weiss、René Peters
DOI:10.1002/chem.200900712
日期:2009.9.7
has a broader substrate tolerance than all previously known catalyst systems for asymmetric aza‐Claisen rearrangements. Our investigations also reveal that subtle changes can have a big impact on the activity. With the enhanced catalyst activity, the asymmetric aza‐Claisen rearrangement has a very broad scope: the methodology not only allows the formation of highly enantioenriched primary allylic amines
Kinetic and Computational Analysis of the Palladium(II)-Catalyzed Asymmetric Allylic Trichloroacetimidate Rearrangement: Development of a Model for Enantioselectivity
作者:Mary P. Watson、Larry E. Overman、Robert G. Bergman
DOI:10.1021/ja0676962
日期:2007.4.1
cyclization-induced rearrangement mechanism and prompted DFT studies (B3LYP/LACVP**+) of C-N bond formation, believed to be the enantiodetermining step of this catalytic cycle. On the basis of these calculations, a model for enantioinduction was developed, in which the planar chirality of the catalyst controls the enantioselectivity. These studies should allow the rational design of more enantioselective catalysts
由 COP 家族的钯 (II) 配合物催化的烯丙基三氯乙酰亚胺的不对称重排是从前手性烯丙醇制备对映体富集的手性烯丙胺的有效方法。对该反应进行了详细的动力学分析,以阐明这一重要反应的速率和对映体决定步骤。这些研究的结果支持环化诱导的重排机制,并促进了 CN 键形成的 DFT 研究 (B3LYP/LACVP**+),据信是该催化循环的对映体决定步骤。在这些计算的基础上,开发了一种对映诱导模型,其中催化剂的平面手性控制对映选择性。这些研究应该允许合理设计更具对映选择性的催化剂。
Catalytic Asymmetric Synthesis of Branched Chiral Allylic Phenyl Ethers from (E)-Allylic Alcohols
作者:Angelaâ C. Olson、Larryâ E. Overman、Helenâ F. Sneddon、Josephâ W. Ziller
DOI:10.1002/adsc.200900678
日期:2009.12
family are reported and characterized crystallographically. The di-mu-amidate complex 3 or its enantiomer (ent-3) are the first asymmetric catalysts that allow commercially available, or readily accessible, (E)-2-alkene-1-ols to be transformed to enantioenriched branched allylic aryl ethers upon reaction of their trichloroacetimidate derivatives with phenols. The 3-aryloxy-1-alkene products are formed
报道了第一个二-mu-酰胺二钯配合物和一种新的 COP(钴恶唑啉钯环)钯 (II) 催化剂家族的二-mu-羧酸二钯配合物,并进行了晶体学表征。二-mu-酰胺配合物 3 或其对映异构体 (ent-3) 是第一个不对称催化剂,它允许市售或容易获得的 (E)-2-烯烃-1-醇转化为对映体富集的支链烯丙基芳基醚它们的三氯乙酰亚胺衍生物与酚类反应。3-芳氧基-1-烯烃产物以高对映体纯度(通常为90-98%ee)和有用产率(61-88%)形成。
Catalytic Asymmetric Rearrangement of Allylic Trichloroacetimidates. A Practical Method for Preparing Allylic Amines and Congeners of High Enantiomeric Purity
作者:Carolyn E. Anderson、Larry E. Overman
DOI:10.1021/ja037086r
日期:2003.10.1
rearrangement of (E)-allylic trichloroacetimidates to provide transposed allylic trichloroacetamides of high enantiopurity, a transformation that underlies the first truly practical method for transforming prochiral allylicalcohols to enantioenriched allylic amines and congeners. The high functional group compatibility of this asymmetric rearrangement and the demonstrated broad utility in synthesis of the allylic
Monomeric Cobalt Oxazoline Palladacycles (COP). Useful Catalysts for Catalytic Asymmetric Rearrangement of Allylic Trichloroacetimidates
作者:Stefan F. Kirsch、Larry E. Overman、Mary P. Watson
DOI:10.1021/jo0487092
日期:2004.11.1
Cobalt oxazoline palladacycles (COP) containing acetylacetonate and hexafluoroacetylacetonate ligands were prepared as catalysts for the asymmetric rearrangement of allylic trichloroacetimidates. These monomeric catalysts are more soluble than the previously described chloride-bridged dimer COP-Cl (1). COP-hfacac (2) provides rearrangedallylic trichloroacetamides with high enantiomeric purities (91−98%