Polycyclic quinazolinones and rutaecarpine were synthesized from isatoic anhydrides and cyclic amines through an electrochemical method without an external oxidant and transition-metal-catalyst.
Indoles, especially multisubstituted ones, are privileged scaffolds found widely in natural products, bioactive molecules, fine chemicals, and organic functional materials. Although several intramolecular electrochemical cyclization reactions of vinyl anilines to construct indoles have been reported in recent years, the intermolecular process between simple anilines and other readily available synthons, even though dominant, remains relatively unexplored. Herein, we report the intermolecular electro-oxidative cycloaddition of anilines and commercially available 1,3-dicarbonyl compounds. This method provides an alternative route for the synthesis of a broad range of multisubstituted indoles without a transition-metal catalyst or external chemical oxidant.
Herein, we have established a method for the construction of β-keto sulfones through aerobic oxy-sulfonylation of alkynes with sulfinates. The reaction performed employing air as the oxidant and oxygen source. Moreover, this protocol exhibits low consume of sulfinates, short reaction period, and minimal waste. Mechanism study and density functional theory (DFT) calculation showed that the solvent played a significant role in the transformation.
A catalytic Lewis acid regulated reaction between quinone imine ketals (QIKs) and 1,3-dicarbonyl compounds provides a divergent and tunable approach to a variety of skeletons, including a series of 2-aryl-1,3-dicarbonyl compounds, indoles, and benzofurans. The use of lithium chloride and ferrous bromide gives C3-or C2-alkylation products of the QIKs. The combination of ferrous bromide and trifluoromethanesulfonic acid delivers indole derivatives. Sequential hydrolysis and C3-alkylation occur in the presence of ytterbium (III) trifluoromethanesulfonate and stoichiometric amounts of water. When the reaction is performed with trifluoromethanesulfonic acid and stoichiometric amounts of water, benzofuran is obtained. This protocol utilizes mild conditions, exhibits regio-and chemoselectivity, and has broad functional group tolerance.
B(C6F5)3-catalyzed cross-coupling reaction between allylic alcohols and boronic acids with excellent regioselectivity, broad scope and mild conditions.
Branched allylic sulfones are privileged scaffolds widely distributed in bioactive molecules, and organic functional materials. Some methods for the synthesis of allyl sulfones have been developed, such as Tsuji-Prost reaction, hydrosulfonylation and radical addition reactions. Despite these advances, the transition-metal-free hydrosulfonylation of unactive 1,3-diene leading to branched allylic sulfones has rarely explored. Herein, a boron-catalysed highly regioselective hydrosulfonylation of 1,3-diene with sulfinic acid has been explored to construct a broad scope of branched allylic sulfones. The reactions proceed smoothly without the help of transition-metal-catalyst. Abundant structural motifs have also been obtained through simple transformation from the generated allylic sulfone products. Compared with the previous methods, this protocol exhibited advantages as following: 1) readily available starting material without pre-treatment; 2) under the catalysis of inexpensive boron trifluoride etherate, avoidance of transition-metal-catalyst; 3) simple operation and easy scale-up, and does not require dry conditions, an inert atmosphere or a water scavenger; 4) excellent atom economy and regioselectivity.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.