Cobalt-catalyzed regioselective syntheses of indeno[2,1-c]pyridines from nitriles and diynes bearing propargyl fragments.

A highly efficient CoI2/o-phenanthroline catalyzed cycloaddition reaction of diynes bearing TBS protected propargylic alcohol fragments with nitriles has been developed. This methodology offers regioselective access, with good functional group tolerance, to various indeno[2,1-c]pyridine derivatives in moderate to excellent yields. It was found that o-phenanthroline as a bidentate nitrogen ligand showed high efficacy in this cycloaddition reaction.

Transition-Metal-Free Aminoacylation of Ynones with Amides: Synthesis of 3-Carbonyl-4-quinolinones or Functionalized Enaminones.

A transition-metal-free tandem process for the synthesis of substituted quinolin-4(1 H)-ones or enaminones is presented. A base-promoted insertion of ynones into the C-N σ-bond of amides is the key step in this process, which provides the corresponding aminoacylation products in good to high yields. Quinolin-4(1 H)-ones are selectively formed via the subsequent N-cyclization pathway in the cases of ynones bearing an ortho-bromo-substituted aryl ring. Easily accessible starting materials and high atom economy make this procedure attractive.