Abstract
The reactivity of “furan-ynes” in combination with pyridine and quinoline N-oxides in the presence of a Au(I) catalyst, has been studied, enabling the synthesis of three different heterocyclic scaffolds. Selective access to two out of the three possible products, a dihydropyridinone and a furan enone, has been achieved through the fine-tuning of the reaction conditions. The reactions proceed smoothly at room temperature and open-air, and were further extended to a broad substrate scope, thus affording functionalized dihydropyridinones and pyranones.
Highlights
The activation of alkynes toward the attack of a nucleophile by means of gold catalysis is a well-established tool in modern organic synthesis.[1]
This work contributes to extend the wide landscape of synthetic opportunities offered by the powerful combination of gold catalysis and furans, enabling the straightforward synthesis of dihydropyridinones and pyranones through control over the product selectivity and the diastereoselectivity of the reaction
The stationary points were optimized in the gas phase with the DFT M06 functional,[16] with the ONIOM procedure.[17]
Summary
The activation of alkynes toward the attack of a nucleophile by means of gold catalysis is a well-established tool in modern organic synthesis.[1]. In 2014, Echavarren reported that three different types of Au(I) carbenes, generated respectively by rearrangement of propargyl esters, cycloisomerization of 1,6-enynes, and retro-Buchner reaction, underwent intermolecular reaction with furans through related mechanistic pathways, giving access to an array of diverse molecular frames (Scheme 1a).[4] Gold(I) carbenes obtained from propargyl esters were later employed by Tang and Shi in intramolecular reactions with furans, achieving the synthesis of functionalized N-heterocycles and O-bridged tricyclic scaffolds (Scheme 1b).[5] Another relevant class of Au(I) carbenes is represented by α-oxo gold(I) carbenes These reactive intermediates can be accessed by treatment of an alkyne with either a pyridine or quinoline N-oxide in the presence of a Au(I) complex, through nucleophilic attack of the O atom of the N-oxide onto the gold-activated triple bond and subsequent cleavage of the pyridine or quinoline (Scheme 1c).[6] α-Oxo gold(I) carbenes can undergo several reaction pathways, including cyclopropanations, migrations, ring expansions, insertions, and reactions with nucleophiles.[7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
