propargyl carbonates have been developed by using two O-containing functional groups as the traceless assisting groups (AGs). The experimental investigations together with the density functional theory (DFT) calculations revealed that this transformation involves the free OH-directed cleavage of one terminal C–H bond of the alkenyl moiety and regioselective alkyne insertion, followed by OBoc-promoted intramolecular
Electrooxidative Rhodium‐Catalyzed [5+2] Annulations via C−H/O−H Activations
作者:Yulei Wang、João C. A. Oliveira、Zhipeng Lin、Lutz Ackermann
DOI:10.1002/anie.202016895
日期:2021.3.15
five‐ and six‐membered heterocycles. In contrast, we herein describe the first electrochemical metal‐catalyzed [5+2] cycloadditions to assemble valuable seven‐membered benzoxepine skeletons by C−H/O−H activation. The efficient alkyne annulation featured ample substrate scope, using electricity as the only oxidant. Mechanistic studies provided strong support for a rhodium(III/I) regime, involving a
Brønsted acid-catalyzed hydroarylation of activated olefins
作者:Ivana Fleischer、Jola Pospech
DOI:10.1039/c4ra13647k
日期:——
A mild, regiospecific Brønstedacid-catalyzed hydroarylation of activated olefins, capable of the formation of quinone methide-like intermediates, has been investigated. Variously substituted 2- and 4-vinylphenols, 4-vinylaniline or 6-vinyl-naphthalen-2-ol were successfully implemented in a sequential protonation and Friedel–Crafts-type alkylation reaction of electron-rich arenes.
Synthesis of Benzofuranones via Palladium-Catalyzed Intramolecular Alkoxycarbonylation of Alkenylphenols
作者:Vera Hirschbeck、Ivana Fleischer
DOI:10.1002/chem.201705808
日期:2018.2.26
Herein, a new catalytic system to synthesize benzofuranones is reported. A palladium‐catalyzed intramolecular alkoxycarbonylation is employed to generate 3‐substituted‐benzofuran‐2(3H)‐ones from alkenylphenols under mild reaction conditions, linked to an ex situ formation of CO from N‐formylsaccharin. The carefully chosen catalytic system enables an efficient reaction with a novel functional group
Asymmetric Annulation of 3-Alkynylacrylaldehydes with Styrene-Type Olefins by Synergetic Relay Catalysis from AgOAc and Chiral Phosphoric Acid
作者:Hao Zhang、Le Zhu、Shaozhong Wang、Zhu-Jun Yao
DOI:10.1021/jo501196n
日期:2014.8.1
Asymmetric annulation of 3-alkynylacrylaldehydes with 2-hydroxystyrenes has been studied and achieved by synergetic catalysis from AgOAc and chiral phosphoric acid, providing the corresponding multiring products with decent total yields and moderate to excellent enantioselectivities (up to 95% ee). The developed mild multibond-formation cascade reaction involves in situ generation of pyrylium intermediate