Cobalt-mediated [2+2+2] cycloaddition versus C-H and N-H activation of 2-pyridones and pyrazinones with alkynes: a theoretical study.
DFT computations have been executed aimed at illuminating the variety of pathways by which pyridones react with alkynes in the presence of [CpCoL(2)]: NH-2-pyridones furnish N-dienylated ligands (N-H activation pathway), N-methyl-2-pyridones are converted into ligated cyclohexadienes ([2+2+2] cocycloaddition pathway), and N-alkynyl-2-pyridones may undergo either [2+2+2] cocycloaddition or C-dienylation (C-H activation), depending on the length of the tether. The calculations predict the formation of the experimentally observed products, including their regio- and stereochemical make up. In addition, the unusual regiochemical outcome of the all-intramolecular [2+2+2] cycloaddition of N,N'-dipentynylpyrazinedione was rationalized by computation, which led to the discovery of a new mechanism.
Aubert
Corinne
C
Université Pierre et Marie Curie-Paris 6, Laboratoire de Chimie Organique (UMR CNRS 7611), Institut de Chimie Moléculaire (FR 2769), case. 229 place Jussieu, 75252 Paris cedex 05, France.
Gandon
Vincent
V
Geny
Anaïs
A
Heckrodt
Thilo J
TJ
Malacria
Max
M
Paredes
Elisa
E
Vollhardt
K Peter C
KP