prevalent in biologically and medicinally important molecules. Here we report that chiral N‐substituted 2‐pyridones were prepared by enantioselective, organocatalytic aza‐Michaeladditions of halogenated 2‐hydroxypyridines (pyridin‐2(1H)‐ones) to α,β‐unsaturated‐1,4‐dketones or 1,4‐ketoesters. The reactions were optimized by the choice of solvents and systematic screening of Cinchona alkaloid‐based bifunctional
Highlyenantioselective Michael addition of 1,3‐dicarbonyl compounds and nitromethane to 4‐oxo‐4‐arylbutenoates catalyzed by N,N′‐dioxide–Sc(OTf)3 complexes has been developed. Using 0.5–2 mol % catalyst loading, various α‐stereogenic esters were obtained regioselectively with excellent yields (up to 97 %) and enantioselectivities (up to >99 % ee). Moreover, the reaction performed well under nearly
A Catalytic Cross‐Olefination of Diazo Compounds with Sulfoxonium Ylides
作者:James D. Neuhaus、Adriano Bauer、Alexandre Pinto、Nuno Maulide
DOI:10.1002/anie.201809934
日期:2018.12.3
A ruthenium‐catalysed cross‐olefination of diazo compounds and sulfoxonium ylides is presented. Our reaction design exploits the intrinsic difference in reactivity of diazo compounds and sulfoxonium ylides as both carbene precursors and nucleophiles, which results in a highly selective reaction.
Substrate-Controlled, One-Pot Synthesis: Access to Chiral Chroman-2-one and Polycyclic Derivatives
作者:Xue-Li Sun、Ying-Han Chen、Dan-Yang Zhu、Yan Zhang、Yan-Kai Liu
DOI:10.1021/acs.orglett.6b00160
日期:2016.2.19
appropriate choice of electrophiles, one-pot, multicomponent, enantioselective domino reactions have been realized which contain a five-step sequence and provide highly efficient access to potentially bioactive chroman-2-one derivatives as a single diastereoisomer with excellent enantioselectivities and in high yields. This new strategy could significantly improve the previous protocol by directly starting
Enantioselective conjugate addition of aliphatic thiols to divergently activated electron poor alkenes and dienes
作者:Rafał Kowalczyk、Aleksandra J. Wierzba、Przemysław J. Boratyński、Julia Bąkowicz
DOI:10.1016/j.tet.2014.06.035
日期:2014.9
Divergently activated double bonds in electron poor 4-oxo-butenoates and (2E,4E)-6-oxo-2,4-dienoates underwent stereoselective and regioselective addition of mercaptans catalyzed by simple Cinchona alkaloids. Application of quinine and quinidine afforded both enantiomers of the 1,4-adducts with respect to the ketone carbonyl group in ees of up to 80%. Single recrystallization of some adducts resulted