Visible Light-Promoted Synthesis of Spiroepoxy Chromanone Derivatives via a Tandem Oxidation/Radical Cyclization/Epoxidation Process
作者:Sungwoo Jung、Jiyun Kim、Sungwoo Hong
DOI:10.1002/adsc.201701072
日期:2017.11.23
A highly efficient and straightforward approach for the synthesis of spiroepoxy chroman‐4‐one derivatives was developed using a visible light‐enabled tandem radical strategy. The reaction is initiated by the formation of an acyl radical that undergoes intramolecularradical cyclization and epoxidation. The optimal result was obtained with 1 mol% of Ru(bpy)3Cl2⋅6H2O, TBHP, and K2CO3 in i‐PrOAc at room
使用可见光启用的串联自由基策略开发了一种高效且直接的合成螺环氧基苯并吡喃-4-酮衍生物的方法。通过形成经历分子内自由基环化和环氧化的酰基自由基来引发反应。用1mol%的Ru获得的最优结果(BPY)3氯2 ⋅6H 2 O,TBHP,和K 2 CO 3在我-PrOAc在室温下与来自蓝色LED照射。这种前所未有的串联方法利用了广泛的底物,并提供了一种方便而强大的合成工具,可用于获得合成上有用的螺环苯并二氢吡喃-4-酮及其含氮衍生物。
2,6-Dimethoxyphenyl-Substituted N-Heterocyclic Carbenes (NHCs): A Family of Highly Electron-Rich Organocatalysts
Based on our recent finding that 2,6-dimethoxyphenyl-substitutedNHCs show superior reactivity in the hydroacylation reactions of electron-neutral olefins compared with known NHCs, we now report the syntheses and crystal structures of four highlyelectron-rich2,6-dimethoxyphenyl-substitutedNHCs and show the increase in efficiency caused by the electron-rich aryl substituent in hydroacylation reactions
A Stereoselective Intramolecular 1,3-Dipolar Nitrone Cycloaddition for the Synthesis of Substituted Chromanes
作者:Qian Zhao、Fusen Han、Donna L. Romero
DOI:10.1021/jo011015y
日期:2002.5.1
A stereoselective intramolecular 1,3-dipolar nitrone cycloaddition useful in the synthesis of chromanes is described. The reaction relies on the use of a chiral auxiliary on the nitrone partner. Key to the success of the reaction is the choice of auxiliary and the choice of Lewis acid catalyst. Utilizing an auxiliary with a pendant coordinating group, and Zn(OTf)(2) as the Lewis acid, diastereoselectivities
N-Heterocyclic Carbene-Catalyzed Hydroacylation of Unactivated Double Bonds
作者:Keiichi Hirano、Akkattu T. Biju、Isabel Piel、Frank Glorius
DOI:10.1021/ja906361g
日期:2009.10.14
An intramolecular N-heterocyclic carbene (NHC)-catalyzed hydroacylation of unactivated double bonds is reported. Systematic variation of the catalyst structure revealed an N-mesitylthiazolylidene annulated with a seven-membered ring to be especially reactive. This NHC enables a unique C-C bond-forming reaction to afford substituted chroman-4-ones in moderate to excellent yields, even ones containing all-carbon quaternary centers.
3-Hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors. 2. Structural modification of 7-(substituted aryl)-3,5-dihydroxy-6-heptenoic acids and their lactone derivatives
作者:William F. Hoffman、A. W. Alberts、E. J. Cragoe、A. A. Deana、B. E. Evans、J. L. Gilfillan、N. P. Gould、J. W. Huff、F. C. Novello
DOI:10.1021/jm00152a001
日期:1986.2
A series of 7-(substituted aryl)-3,5-dihydroxy-6-heptenoic (heptanoic) acids and their lactone derivatives have been prepared and tested for inhibition of 3-hydroxy-3-methylglutaryl-coenzyme A reductase in vitro. A systematic exploration of the structure-activity relationships in this series led to the synthesis of (+)-trans-(E)-6-[2-[2,4-dichloro-6-[(4-fluorophenyl) methoxyl]phenyl]ethyl]-3,4,5,6-tetrahydro-4-hydroxy-2H-pyran-2-one (66(+)), which has one-half of the inhibitory activity of compactin.