phenol as a directing group, high regioselectivity, good substrate scope, mild reaction conditions, and high efficiency. To the best of our knowledge, this is the first example of a regioselective C−H alkenylation of unprotected phenols utilizing phenolic hydroxyl group as a directing group. The alkenylation of unprotected tyrosine and intramolecular cyclization are also successfully carried out under
Six‐membered ring fused furans containing a tetrasubstituted tertiary carbon were prepared in an unprecedented one‐pot BODIPY‐catalyzed domino photooxygenation/reduction process. A series of functionalized furans was synthesized from readily available 2‐alkenylphenols and mechanistic studies were performed to account for the domino photosensitized oxygenation.
Cascade Synthesis of 4-Arylcoumarins: Pd-Catalyzed Arylations and Cyclizations with (<i>E</i>
)-Ethyl 3-(2-Hydroxyaryl)acrylates and Triarylantimony Difluorides
The reactions of 3‐(2‐hydroxyaryl)acrylates with triarylantimony difluorides in the presence of Pd(OAc)2 and 2,2'‐bipyridyl under aerobic conditions afforded 4‐arylcoumarins in good‐to‐excellent yields with all of the arylgroups in the triarylantimony difluoride transferred to the coupling products. This protocol increases the synthetic scope of 4‐arylcoumarins, especially those bearing electron‐withdrawing
Coumarins from Free <i>ortho</i>-Hydroxy Cinnamates by Heck-Matsuda Arylations: A Scalable Total Synthesis of (<i>R</i>)-Tolterodine
作者:Daniela A. Barancelli、Airton G. Salles、Jason G. Taylor、Carlos Roque D. Correia
DOI:10.1021/ol302923f
日期:2012.12.7
Free ortho-hydroxy cinnamate ester derivatives are evaluated in the synthesis of structurally diverse 4-aryl-coumarins via a tandem Heck-Matsuda cyclization reaction. Free phenolic groups were considered incompatible with such a reaction, which usually provide the corresponding diazo dyes. A concise and scalable route employing a ligand-free, Pd-catalyzed Heck-Matsuda arylation under aerobic conditions
Multicatalytic dearomatization of phenols into epoxyquinols <i>via</i> a photooxygenation process
作者:Louis Péault、Pierrick Nun、Erwan Le Grognec、Vincent Coeffard
DOI:10.1039/c9cc03068a
日期:——
A multicatalytic photooxygenation of substituted phenols in the presence of rose bengal and cesium carbonate under green LED light is reported. This transformation enabled the introduction of both atoms of singlet oxygen and led to the one-pot synthesis of epoxyquinols in a stereoselective way.