Manuel R. Fructos

Selective Synthesis of N-Substituted 1,2-Dihydropyridines from Furans by Copper-Induced Concurrent Tandem Catalysis

A novel transformation in which mono- or dialkyl-substituted furans are converted into 1,2-dihydropyridines upon reaction with PhI horizontal lineNTs at room temperature is reported. The reaction is catalyzed by complexes of general formula Tp(x)M (M = Cu, Ag) and consists of a one-pot procedure with four consecutive catalytic cycles. Furan aziridination is followed by aziridine ring-opening, transimination reaction, inverse-electronic-demand aza-Diels-Alder reaction, and a final hydrogen elimination reaction. The mechanism of the overall transformation is proposed where the metal complex displays a crucial role along the reaction pathway.

Highly active gold-based catalyst for the reaction of benzaldehyde with ethyl diazoacetate

The gold complex [IPrAu(NCMe)]BF(4) catalyzes the reaction of ethyl diazoacetate with benzaldehyde to give mixtures of ethyl 3-oxo-3-phenylpropanoate and ethyl 3-hydroxy-2-phenylacrylate in the first example of a group 11 metal-based catalyst for this transformation; the catalyst activity is improved by a factor of 2500 compared to those of previously reported iron-based catalysts.

Alkane Catalytic Functionalization by Carbene or Nitrene Insertion Reactions

The functionalization of carbon-hydrogen bonds of alkanes by means of the insertion of carbene (CR2) or nitrene (NR) units are presented in this chapter. Developed at different extends, the former methodology has received much attention, probably due to the use of available diazo compounds as the carbene source. For the NR case, the sources are usually based in hypervalent iodine compounds. In both cases, a yet reduced number of catalytic systems have been reported for the conversion of plain, non-activated alkanes into value added products. The development of these methodologies, current state of the art, including asymmetric systems and mechanistic considerations are described.

The Elusive Palladium-Diazo Adduct Captured: Synthesis, Isolation and Structural Characterization of [(ArNHC-PPh2)Pd(η2-N2C(Ph)CO2Et)]

The first example of a diazo palladium adduct is reported. The complexes [(ArNHC-PPh2 )M(η2 -N2 C(Ph)CO2 Et)] (M=Ni, 3; M=Pd, 4; ArNHC-PPh2 =3-(2,6-diisopropylphenyl)-1-[(diphenylphosphino)ethyl]imidazol-2-ylidene) were prepared by ligand exchange with styrene-coordinated precursors [(ArNHC-PPh2 )M(styrene)] (M=Ni, 1; M=Pd, 2). Complex 4 was fully characterized, including X-ray analyses; this constitutes the first example of a diazo adduct compound with palladium, thereby closing the gap between Groups 8 and 10 regarding this type of compounds.

Evidencing an inner-sphere mechanism for NHC-Au(I)-catalyzed carbene-transfer reactions from ethyl diazoacetate

Summary Kinetic experiments based on the measurement of nitrogen evolution in the reaction of ethyl diazoacetate (N2CHCO2Et, EDA) and styrene or methanol catalyzed by the [IPrAu]+ core (IPr = 1,3-bis(diisopropylphenyl)imidazole-2-ylidene) have provided evidence that the transfer of the carbene group CHCO2Et to the substrate (styrene or methanol) takes place in the coordination sphere of Au(I) by means of an inner-sphere mechanism, in contrast to the generally accepted proposal of outer-sphere mechanisms for Au(I)-catalyzed reactions.

CCDC 1443209: Experimental Crystal Structure Determination

Related Article: Maria Alvarez, Eleuterio Alvarez, Manuel R. Fructos, Juan Urbano, Pedro J. Perez|2016|Dalton Trans.|45|14628|doi:10.1039/C5DT04972E

CCDC 1443212: Experimental Crystal Structure Determination

Related Article: Maria Alvarez, Eleuterio Alvarez, Manuel R. Fructos, Juan Urbano, Pedro J. Perez|2016|Dalton Trans.|45|14628|doi:10.1039/C5DT04972E