ESI-MS studies of the dehydrogenative Heck reaction of furans with acrylates using benzoquinone as the reoxidant and DMSO as the solvent.
Electrospray ionization mass spectrometry, subsequent MS/MS, and high-resolution mass spectrometry were used to study the dehydrogenative Heck reaction of 2-alkylfurans 1 with acrylates 2, using [Pd(OAc)(2)](3) as the precatalyst, benzoquinone (BQ) as the stoichiometric oxidant, and a mixture of DMSO and AcOH as the solvent. Complexation of [Pd(OAc)(2)](3) by DMSO afforded mononuclear and dinuclear Pd(II) species, which proved to be active catalysts for the C-H activation of 1. Mononuclear and dinuclear Pd(II) species seem also to be involved in the insertion of 2 into the furyl-Pd bond. The C-H activation of 2 and DMSO by mononuclear complexes was observed. The reaction leads to 5,5'-dialkyl-2,2'-bifuran 4 as a byproduct. Bifuryl-palladium, which is an intermediate in the formation of 4, showing the coordination of BQ, was obtained and characterized.
Institut de Chimie Moléculaire de Reims-UMR 7312 CNRS-Université de Reims Champagne-Ardenne UFR des Sciences Exactes et Naturelles, BP 1039, 51687 REIMS Cedex 2, France.
Alexandre
A
Vasseur
Dominique
D
Harakat
Jacques
J
Muzart
Jean
J
Le Bras
D000179:Acrylates / Q000737:chemistry*; D016227:Benzoquinones / Q000737:chemistry*; D004121:Dimethyl Sulfoxide / Q000737:chemistry*; D005663:Furans / Q000138:chemical synthesis / Q000737:chemistry*; D006865:Hydrogenation; D010084:Oxidation-Reduction; D012997:Solvents / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization
D000179:Acrylates; D016227:Benzoquinones; D005663:Furans; D012997:Solvents; C004532:quinone; D004121:Dimethyl Sulfoxide