Evaluation of Catalyst Acidity and Substrate Electronic Effects in a Hydrogen Bond-Catalyzed Enantioselective Reaction
作者:Katrina H. Jensen、Matthew S. Sigman
DOI:10.1021/jo1013806
日期:2010.11.5
A modular catalyst structure was applied to evaluate the effects of catalystacidity in a hydrogen bond-catalyzed hetero Diels−Alder reaction. Linear free energy relationships between catalystacidity and both rate and enantioselectivity were observed, where greater catalystacidity leads to increased activity and enantioselectivity. A relationship between reactant electronic nature and rate was also
Assembled Dendritic Titanium Catalysts for Enantioselective Hetero-Diels–Alder Reaction of Aldehydes with Danishefsky's Diene
作者:Baoming Ji、Yu Yuan、Kuiling Ding、Jiben Meng
DOI:10.1002/chem.200305286
日期:2003.12.15
titanium-catalyzed hetero-Diels-Alderreaction of Danishefsky's diene with aldehydes. These reactions afforded the corresponding 2-substituted 2,3-dihydro-4H-pyran-4-ones in quantitative yields and with excellent enantioselectivities (up to 97.2 % ee). The disposition of the dendritic wedges and the dendron size in the ligands were found to have significant impact on the enantioselectivity of the reaction. The recovered
Various heterogeneously or homogeneously hybridized salen/salan ligands were synthesized, and study of hetero Diels–Alder reactions using their chromium complexes as catalysts revealed that a well-designed heterogeneously hybridized ligand serves as a chiral auxiliary as efficiently as the homogeneously hybridized ligand and its chromium complex has high catalytic activity.
Methods of performing cycloadditions, reaction mixtures, and methods of performing asymmetric catalytic reactions
申请人:The University of Chicago
公开号:US07230125B1
公开(公告)日:2007-06-12
Methods of performing cycloadditions are described that include (a) combining a first reactant and a second reactant in a hydrogen bonding solvent to form a reaction mixture; and (b) reacting the first reactant and the second reactant to form a cycloadduct. Methods of performing asymmetric catalytic reactions are also described that include (a) combining a first reactant, a second reactant, and a catalytic amount of a chiral hydrogen-bond donor in a solvent to form a reaction mixture; and (b) reacting the first reactant and the second reactant to form an enantiomeric excess of a reaction product. Reaction mixtures corresponding to these methods are also described.
A Family of Chiral Ferrocenyl Diols: Modular Synthesis, Solid-State Characterization, and Application in Asymmetric Organocatalysis
作者:Chris Nottingham、Helge Müller-Bunz、Patrick J. Guiry
DOI:10.1002/anie.201604840
日期:2016.9.5
Readily available chiral diol scaffolds are useful as sources of chirality for asymmetric synthesis, however, few such scaffolds are readily available in enantiopure form. Reported herein is a cheap and modularsynthesis of a novel family of chiral ferrocenyl diols in excellent yields with excellent enantio‐ and diastereoselectivity (>99 % ee and 99 % de). These diols possess not only planar and central