No abstract

The palladium‐catalyzed domino intermolecular C(sp2)–H activation reaction of two aryl iodides was explored. This simple palladium catalytic system showed good activity.

A simple and recyclable catalytic system for direct arylation of heteroarenes via C-H bond activation was developed with a relatively inexpensive RuCl 3 $xH 2 O as a catalyst and PEG-400 as a green medium without any additive or ligand. This system not only showed excellent functional group compatibility, but also the ratio of mono-to diarylated product was easily regulated by varying the reaction conditions. Moreover, this transformation could proceed under air and be easily scaled up to gram-scale in a low catalyst loading of 0.3 mol%. Particularly, a good yield of 85% was obtained after this catalyst was recycled six times.

A simple and efficient strategy for the synthesis of 1-propenylnaphthols from readily accessible 3-arylallylnaphthyl ethers has been developed. By using KCO as base and 2-methoxyethanol as solvent, direct access to a wide range of 1-propenylnaphthols can be achieved in generally good yield (up to 99%) with high stereoselectivity toward the Z isomer. The control experiments indicate that the reaction proceeds through a sequential Claisen rearrangement/isomerization process. Furthermore, starting from the same material, the highly valuable 3-arylnaphtho[2,1-b]furans can be obtained in N,N-dimethylformamide and in the presence of AgO as the oxidant via a one-pot sequential Claisen rearrangement/isomerization/cyclization reaction. Mechanistic studies confirm that 1-propenylnaphthols are the key intermediates to form the 3-arylnaphtho[2,1-b]furans. In addition, these two operationally simple and practical protocols could be scaled up to a gram level.