We report the first example of cooperative catalysis by DBU and CuCl2, which allows the carboxylation of homopropargylic amines to high value added 6-methylene-1,3-oxazin-2-ones. This reaction also represents the first efficient method for the catalytic incorporation of CO2 into an acyclic substrate to give oxazinones. DFT calculations are in agreement with a mechanism involving: a) deprotonation of the substrate by DBU; b) CO2 capture with formation of a copper carbamate; c) 6-exo-dig cyclization through intramolecular triple bond insertion; and d) protonolysis, with regeneration of DBU and CuCl2 catalysts. The structure of a representative product has been confirmed by XDR analysis.
Mancuso R., Ziccarelli I., Pomelli C.S., Cuocci C., Della Ca' N., Olivieri D., et al. (2020). Unprecedented cooperative DBU-CuCl2 catalysis for the incorporation of carbon dioxide into homopropargylic amines leading to 6-methylene-1,3-oxazin-2-ones. JOURNAL OF CATALYSIS, 387, 145-153 [10.1016/j.jcat.2020.03.033].
Unprecedented cooperative DBU-CuCl2 catalysis for the incorporation of carbon dioxide into homopropargylic amines leading to 6-methylene-1,3-oxazin-2-ones
Olivieri D.;Carfagna C.;
2020
Abstract
We report the first example of cooperative catalysis by DBU and CuCl2, which allows the carboxylation of homopropargylic amines to high value added 6-methylene-1,3-oxazin-2-ones. This reaction also represents the first efficient method for the catalytic incorporation of CO2 into an acyclic substrate to give oxazinones. DFT calculations are in agreement with a mechanism involving: a) deprotonation of the substrate by DBU; b) CO2 capture with formation of a copper carbamate; c) 6-exo-dig cyclization through intramolecular triple bond insertion; and d) protonolysis, with regeneration of DBU and CuCl2 catalysts. The structure of a representative product has been confirmed by XDR analysis.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
