The first "in air" copper-catalyzed method for the selective synthesis of tri-and tetrasubstituted vinylboronate derivatives is presented. Three different variants of the borylation of internal alkynes (α-hydroboration, β-hydroboration, and carboboration) are described using a single catalyst: [Cu(Cl)(IMes)] (IMes = N,N′-bis-[2,4,6-(trimethyl)phenyl]imidazol-2-ylidene) without taking any precaution to avoid the presence of air. Bis(pinacolato)diboron was used to afford β-hydroborated products in the presence of methanol. Adding instead another electrophile allowed the formation of tetrasubstituted vinylboronate species. Finally, the α-products were obtained using pinacolborane as the boron source. All compounds were obtained in high yield with excellent regioselectivity at low catalyst loading (0.04−2 mol %). The protocol constitutes a very convenient route to access these highly valuable molecules.
Thes ynthesis andc haracterization of abnormal N-heterocyclic carbene,c yclic (alkyl)(amino)carbene,a nd mesoionic carbene copper(I) complexesa re reported.T hese organometallic species are obtained via aversatile and inexpensive synthetic pathwayu sing readily available reactants,n amely copper oxide andi miniums alts.T he catalytic activity of this series of complexes was evaluated in the [3+ +2] cycloaddition of alkynes with azides (CuAAC). Outstanding catalytic properties were observed for the abnormal NHC-a nd triazolylidenebased copper(I) complexes.
We report the first example of BAC-Cu complex (BAC = bis(diisopropylamino)cyclopropenylidene) and its use as a carbene-transfer reagent, allowing access to Au-, Pd-, Ir-and Rh-BAC compounds. Catalytic experiments show the high activity of the [CuCl(BAC)] complex in Click chemistry.
MFI-type materials with a lamellar morphology were successfully synthesized by using mononitrogen surfactants specifically designed by molecular modelling. The mononitrogen surfactants directed the recrystallization of a crystalline layered polysilicate formed in situ, the magadiite, into a zeolite ZSM-5.Moreover, the surfactants allow the preservation of the lamellar shape of the magadiite and inhibit a further growth into one dimension, leading to the formation of zeolite ZSM-5 nanosheets with a thickness comprised between 2 and 3 nm and a Si/Al ratio of 24. This simple approach paves a new way for obtaining zeolite materials of controlled size and shape for specific catalytic applications.
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