Catalytic Enantioselective Synthesis of Flavanones and Chromanones
摘要:
The enantioselective synthesis of flavanones and chromanones is described. Bifunctional thiourea catalysts promote an asymmetric oxo-conjugate addition to a beta-ketoester alkylidene in high yields with excellent enantioselectivity (80-94% ee) for aryl and alkyl substrates. Decarboxylation of the beta-ketoester proceeds smoothly in a one-pot procedure to afford the enantioenriched flavanones and chromanones.
Asymmetric Ion-Pairing Catalysis of the Reversible Cyclization of 2′-Hydroxychalcone to Flavanone: Asymmetric Catalysis of an Equilibrating Reaction
作者:Lukas Hintermann、Claudia Dittmer
DOI:10.1002/ejoc.201200838
日期:2012.10
The asymmetric catalytic cyclization of the simple 2′-hydroxychalcone (1) to flavanone (2), a model for the chalcone isomerase reaction, has been realized as a catalytic asymmetric ion-pairing process with chiral quaternary ammonium salts (e.g., 9-anthracenylmethlycinchoninium chloride; 9-Am-CN-Cl) and NaH as small-molecule co-catalyst. In toluene/CHCl3 solution, the process reaches an intrinsic enantioselectivity
frontier in the development of chiral stationary phases for chromatographic enantioseparation involves homochiral metal–organic frameworks (MOFs). Using enantiopure (R)-2,2′-dihydroxy-1,1′-binaphthalene-6,6′-dicarboxylic acid as a starting material, we prepared three homochiral MOFs that were further used as chiral stationary phases for high-performanceliquidchromatography to separate the enantiomers
Rhodium/Chiral Diene-Catalyzed Asymmetric 1,4-Addition of Arylboronic Acids to Chromones: A Highly Enantioselective Pathway for Accessing Chiral Flavanones
作者:Qijie He、Chau Ming So、Zhaoxiang Bian、Tamio Hayashi、Jun Wang
DOI:10.1002/asia.201403290
日期:2015.3
Chromone has been noted to be one of the most challenging substrates in the asymmetric 1,4‐addition of α,β‐unsaturated carbonyl compounds. By employing the rhodium complex associated with a chiral diene ligand, (R,R)‐Ph‐bod*, the 1,4‐addition of a variety of arylboronicacids was realized to give high yields of the corresponding flavanones with excellent enantioselectivities (≥97 % ee, 99 % ee for