Two- or one-electron-mediated difunctionalizations of internal alkenes represent straightforward approaches to assemble molecular complexity by the simultaneous formation of two contiguous Csp3 stereocentres. Although racemic versions have been extensively explored, asymmetric variants, especially those involving open-shell C-centred radical species, are much more limited both in number and scope. Here we describe enantioenriched arylsulfinylamides as all-in-one reagents for the efficient asymmetric, intermolecular aminoarylation of alkenes. Under mild photoredox conditions, nitrogen addition of the arylsulfinylamide onto the double bond, followed by 1,4-translocation of the aromatic ring, produce, in a single operation, the corresponding aminoarylation adducts in enantiomerically enriched form. The sulfinyl group acts here as a traceless chiral auxiliary, as it is eliminated in situ under the mild reaction conditions. Optically pure β,β-diarylethylamines, aryl-α,β-ethylenediamines and α-aryl-β-aminoalcohols, prominent motifs in pharmaceuticals, bioactive natural products and ligands for transition metals, are thereby accessible with excellent levels of regio-, relative and absolute stereocontrol.
The total synthesis of Laetevirenol A, a natural product with antioxidant activity, has been achieved. A gold-catalyzed cycloisomerization of an o-alkenyl-o’-alkynylbiphenyl has been used as the key step for the construction of the phenanthrene moiety present in Laetevirenol A. Several studies in model substrates have been carried out to unveil the effect of substituents in different locations in the outcome of this cyclization, which allowed the design of an appropriate precursor for the fundamental gold-catalyzed cycloisomerization. The suitably functionalized phenanthrene intermediate obtained in this key step could be further transformed into Laetevirenol A via a Friedel-Crafts cyclization, which also turned out to be dependent on the nature of the substituents. Finally, Laetevirenol A was obtained in 10 steps from commercially available substrates, with a 20% global yield.
La Dra. Patricia García ha recibido el premio a director novel de las ramas de ciencias, ciencias de la salud, ingeniería y arquitectura en la convocatoria 2023.
Este premio supone un reconocimiento al trabajo que el profesorado de la Universidad de Alcalá realiza por la obtención de resultados en el ámbito de la formación de investigadores
¡Enhorabuena!
An efficient methodology to form 4-alkoxy- and 4-aryloxybenzo[d][1,2,3]triazines via an intramolecular heterocyclization of 1-azido-2-[isocyano(p-tosyl)methyl]benzenes under basic conditions has been developed. DFT calculations have been performed to further understand the mechanism of this heterocyclization, which occurs in good to excellent yields with a broad scope.
XXV EuCOMC, XXV CONFERENCE ON ORGANOMETALLIC CHEMISTRY
Alcalá de Henares, 4 – 8 septiembre
– Póster: · Copper-catalyzed intramolecular cyclization of alkynylazobenzenes for the synthesis of 2H-indazoles Clara Mañas, Juan Herrero, Estíbaliz Merino
– Póster: · Visible-Light-Mediated Regioselective Chlorosulfonylation of Acrylamides Guillermo G. Otárola, Mercedes Zurro, Sergio Torres-Oya, Juan José Vaquero, Estíbaliz Merino
– Póster: · Direct conversion of C1−C6 alkanes into trifluoromethyl derivatives Jonathan Martínez-Laguna, M. Ángeles Fuentes, Julia Altarejos, Javier Carreras, Ana Caballero, Pedro J. Pérez
Synthesis of anticancer drug bicalutamide promoted by visible light in one step from the corresponding N-arylacrylamide is described. This approach involves a one-pot hydroxysulfonylation reaction via a photocatalytic redox process. The use of Na2Eosin Y as photocatalyst and blue light allows the access to a broad range of α-hydroxysulfonylamides bearing a quaternary center in moderate to good yields with complete regioselectivity via radical process.
A facile access to 5-aryl-3-trifluoromethylpyrazoles has been developed by a one-pot (3 + 2) cycloaddition–isomerization–oxidation sequence employing 2,2,2-trifluorodiazoethane and styryl derivatives. A broad variety of functional groups and good yields are achieved under mild conditions. Additionally, the functionalization of 3-trifluoromethylpyrazoles was studied. DFT calculations of the cycloaddition transition state energies are consistent with the experimentally observed reactivity.
El profesor Juan José Vaquero pasará en septiembre a ser Profesor Emérito, tras una dilatada y exitosa trayectoria en la UAH.
Su grupo le organizó un homenaje junto con compañeros, antiguos colaboradores y amigos.
A general method for the functionalization of 4a-aza-8a-boranaphthalene in the position β to the nitrogen atom has been developed. This method is based on a regioselective iridium-catalyzed C−H activation process for the introduction of a boronate group, which can subsequently be transformed into a variety of aryl or alkynyl groups via cross-coupling reactions. Selective mono- or difunctionalization can be achieved by controlling the reaction conditions during the borylation step. The photophysical properties of the obtained 3- or 3,6-substituted BN-naphthalenes have been evaluated, and some of them have been found to be significantly fluorescent, with fluorescence quantum yields up to 0.85.
