Herein, we report a novel synthesis of 1,3-oxazin-6-ones from enamides with CO 2 through C-H carboxylation and one-pot cyclization. This transition-metal-free and redox-neutral process features broad substrate scope, good functional group tolerance and facile product derivatization. The nucleophilic attack to CO 2 from the electron-rich alkene is demonstrated for this reaction.At the beginning, we made a lot of attempts based on previous reactions conditions and only detected the carboxylation products. As the cyclization products, 1,3-oxazin-6-ones, are highly important and can been easily obtained via cyclization in
The first catalytic lactonization of unactivated aryl C-H bonds with CO to afford important phthalides is reported. Notably, this method features high selectivity, excellent functional group tolerance, smooth scalability, and facile product diversification. DFT calculations reveal that a novel insertion of two CO into the O-Pd bond of a palladacycle might be the key step, providing great potential and a different perspective for carbonylation with CO.
The back cover picture shows a novel synthesis of 1,3‐oxazin‐6‐ones from enamides with CO2 through C—H carboxylation and one‐pot cyclization. The concept of “CO2 = CO + O”, using CO2 to replace toxic CO and stoichiometric oxidant, guilds the development of this chemistry as well as green and safe synthetic methods in the future. More details are discussed in the article by Yu et al. on page 430–436.
The transition-metal-free lactonization of heteroaryl and alkenyl C-H bonds with carbon dioxide is reported to synthesize important coumarin derivatives in moderate to excellent yields. These redox-neutral reactions feature a broad substrate scope, good functional group tolerance, facile scalability, and easy product derivatization.
Organosilicon compounds have been extensively utilized both in industry and academia. Studies on the syntheses of diverse organosilanes is highly appealing. Through‐space metal/hydrogen shifts allow functionalization of C−H bonds at a remote site, which are otherwise difficult to achieve. However, until now, an aryl to alkyl 1,5‐palladium migration process seems to have not been presented. Reported herein is the remote olefination, arylation, and borylation of a methyl group on silicon to access diverse vinyl‐, benzyl‐, and borylsilanes, constituting a unique C(sp3)−H transformation based on a 1,5‐palladium migration process.
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