One‐Pot Synthesis of Highly Substituted Polyheteroaromatic Compounds by Rhodium(III)‐Catalyzed Multiple C?H Activation and Annulation

A new method for the synthesis of highly substituted naphthyridine‐based polyheteroaromatic compounds in high yields proceeds through rhodium(III)‐catalyzed multiple C H bond cleavage and C C and C N bond formation in a one‐pot process. Such highly substituted polyheteroaromatic compounds have attracted much attention because of their unique π‐conjugation, which make them suitable materials for organic semiconductors and luminescent materials. Furthermore, a possible mechanism, which involves multiple chelation‐assisted ortho C H activation, alkyne insertion, and reductive elimination, is proposed for this transformation.     

Synthesis of biarylketones and phthalides from organoboronic acids and aldehydes catalyzed by cobalt complexes

A cobalt-catalyzed addition of aryl- and alkenylboronic acids to aldehydes and phthalaldehyde to give the corresponding biarylketones and 3-aryl phthalides in good to excellent yields in one pot is described.     

Studies towards iodine-catalyzed dehydrative-cycloisomerization of pent-4-yne-1,2-diols to di- and tri-substituted furans

An efficient and single-step iodine catalyzed and metal-free synthesis of di and tri-substituted 2-methylfuran derivatives were achieved from 1-popargyl-1,2-diols. Stereospecific synthesis of starting 1,2-diols was achieved by indium mediated Barbier type propargylation on corresponding keto-alcohols or by sodium borohydride mediated reduction of 2-hydroxy-2-propargyl ketones. The furan synthesis proceeded through iodine mediated 5-exo-trig cyclization, dehydration and reductive deiodination. The method was applied to the synthesis of 2-methylfuran fused to phenanthrene, pyrene and acenaphthylene rings.     

Ru(II)-Catalyzed Amidation of 2-Arylpyridines with Isocyanates via C-H Activation

An efficient Ru(II)-catalyzed amidation of 2-arylpyridines with isocyanates via C-H bond activation is described.     

Synthesis of isochromenones and oxepines via Pd-catalyzed cascade cyclization of alkynes and benzynes involving C-H activation

A new method for the synthesis of various isochromen-6-ones and phenanthro[1,10-bc]oxepines via a palladium-catalyzed cascade carbocyclization of 2-iodobenzyl-3-phenylpropiolates and 1-iodo-2-(2-(phenylethynyl)benzyloxy)benzenes with arynes is described. The reactions involve interesting biscarbocyclization of alkynes and benzynes and C-H bond activation.     

Synthesis of Phenanthridinones from N‐Methoxybenzamides and Aryltriethoxysilanes through RhIII‐Catalyzed C?H and N?H Bond Activation

An efficient method for the one‐pot synthesis of substituted phenanthridinone derivatives from N‐methoxybenzamides and aryltriethoxysilanes through rhodium‐catalyzed dual C? H bond activation and annulation reactions is described. A double‐cycle mechanism is proposed to account for this catalytic reaction. In addition, isotope‐labeling studies were performed to understand the intimate mechanism of the reaction.