Palladium-Catalyzed Asymmetric Conjugate Addition of Arylboronic Acids to Heterocyclic Acceptors
作者:Jeffrey C. Holder、Alexander N. Marziale、Michele Gatti、Bin Mao、Brian M. Stoltz
DOI:10.1002/chem.201203643
日期:2013.1.2
Flava Flavanone: Asymmetricconjugateadditions to chromones and 4‐quinolones are reported utilizing a single catalyst system formed in situ from Pd(OCOCF3)2 and (S)‐tBuPyOX. Notably, these reactions are performed in wet solvent under ambient atmosphere, and employ readily available arylboronicacids as the nucleophile, thus providing ready access to these asymmetric heterocycles (see scheme).
Synthetic approach to flavanones and flavones via ligand-free palladium(ii)-catalyzed conjugate addition of arylboronic acids to chromones
作者:Donghee Kim、Kyungrok Ham、Sungwoo Hong
DOI:10.1039/c2ob26061a
日期:——
The remarkable catalytic effects of Fe(OTf)3 in the context of the Pd(II)-catalyzed conjugate addition of arylboronic acids to chromones were observed to yield a variety of flavanones under mild conditions. The addition of catalytic amounts of DDQ and KNO2 to the reactions exclusively yielded flavone analogs. The reaction scope for the transformation was fairly broad, affording good yields of a wide range of flavanones and flavones, which are privileged structures in many biologically active compounds.
作者:Po-Yuan Chen、Tzu-Pin Wang、Michael Y. Chiang、Keng-Shian Huang、Cherng-Chyi Tzeng、Yi-Long Chen、Eng-Chi Wang
DOI:10.1016/j.tet.2011.04.070
日期:2011.6
water in the presence of DABCO at roomtemperature gave 3-hydroxy-1-(2-hydroxylphenyl)-3-arylpropan-1-ones (3a–i) as intermediates. Followed by an intramolecular dehydration of the 3a–i with the modified Mitsunobu’s reaction, the target flavanones (4a–i) were obtained. Moreover, the reaction of 1 and 2 at the same conditions but at reflux gave flavanones in onepot with good yields.
Thermal Isomerization Equilibrium between 2′-Hydroxychalcones and Flavanones
作者:Yukio Hoshino、Noboru Takeno
DOI:10.1246/bcsj.59.2903
日期:1986.9
corresponding flavanones were heated separately at 230±0.2 °C in nitrogen atmosphere. Both materials were mutually isomerized under these reaction conditions and the equilibrium constants of this isomerization were measured by means of HPLC analyses. The substituent effect on the equilibrium is discussed and thermodynamic functions (ΔG, ΔH, and ΔS) are calculated.
A protocol for the synthesis of C5-olefinated 2-arylchromanones in a regio- and stereoselective fashion through the ruthenium-catalyzed oxidative coupling of diversified 2-arylchromanones with various alkenes through a keto-directed, site-selective C–Hactivation reaction is developed. IBO = isobornyl.