Nickel‐Catalyzed [2+2+2] Cycloaddition of Diynes and Cyanamides

Abstract

A variety of bicyclic N,N-disubstituted 2-aminopyridines have been prepared from diynes and cyanamides by nickel-catalyzed [2+2+2] cycloaddition reactions. The reactions proceeded at room temperature with low catalyst loading to afford 2-aminopyridines in good to excellent yields. The method is amenable to both internal and terminal diynes and proceeds in a regioselective manner. A number of cyanamides with diverse functional group tolerance were used. The intermolecular version employing 3-hexyne and N-cyanopyrrolidine also afforded the desired N,N-disubstituted 2-aminopyridine in good yield.

A novel family of homoleptic copper(i) complexes featuring disubstituted cyanamides: a combined synthetic, structural, and theoretical study

“…The dialkylcyanamides NCNRR 0 (R/R 0 = Me/Me, Et/Et, C 5 H 10 , C 4 H 8 O, C 4 H 8 ; Aldrich) and solvents were obtained from commercial sources and used as received. The dialkylcyanamides NCN(CH 2 Ph) 2 , NCN(Me)Ph, NCNC 3 H 6 C 6 H 4 , 34 and the copper(I) complex [Cu(NCMe) 4 ](BF 4 ), 35 were synthesized in accord with the published methods. The HRESI mass spectra were obtained on a Bruker micrOTOF spectrometer equipped with an electrospray ionization source and MeOH was employed as the solvent.…”

A Serendipitous Discovery: Nickel Catalyst for the Cycloaddition of Diynes with Unactivated Nitriles

“…[19] These cycloadditions possessed an expanded substrate scope as terminal diynes were successfully converted to pyridine products. However, SIPr was required as a ligand rather than the standard IMes ligand employed for the coupling of internal diynes and cyanamides.…”

Transition metal-catalyzed [2 + 2 + 2] cycloaddition of nitrogen-linked 1,6-diynes: a straightforward route to fused pyrrolidine systems

“…72 Ni-catalyzed cycloaddition of 9a and pyrrolidine-1-carbonitrile, was also reported by the same authors. 73 3.1.6. Iridium.…”