A novel Fe-NHC catalytic system allows the alkyl-alkyl cross-coupling reaction of alkyl halides and alkylmagnesium reagents has been developed. To our knowledge, this is the first Fe-catalysed Kumadatype coupling for the formation of C(sp 3 )-C(sp 3 ) bonds in the presence of functional groups. The process takes place under mild conditions, avoiding the formation of b-elimination products.Mechanistic studies suggest the intermediacy of Fe(I) complexes, formed by reduction with the Grignard reagent, as the active species.

A novel Cu-catalyzed diastereo- and enantioselective desymmetrization of cyclopropenes to afford nonracemic cyclopropylboronates is described. Trapping the cyclopropylcopper intermediate with electrophilic amines allows for the synthesis of cyclopropylaminoboronic esters and demonstrates the potential of the approach for the synthesis of functionalized cyclopropanes.

Esta es la versión de autor del artículo publicado en: This is an author produced version of a paper published in: In this report, the first catalytic enantioselective synthesis of cyclobutylboronates, using a chiral copper(I) complex, is disclosed. A broad variety of cyclobutanes have been prepared with consistently high levels of diastereo-and enantiocontrol. Moreover, this method constitutes the first report of an enantioselective desymmetrization of meso-cyclobutenes to prepare chiral cyclobutanes.

Optimal conditions for a general Ni-catalysed Negishi cross-coupling of alkyl zinc halides with aryl, heteroaryl and alkenyl halides have been determined. These conditions allow the reaction to take place smoothly, with low catalyst loading, and in the presence of a wide variety of functional groups to afford products in good yields at room temperature. DFT studies on the mechanism support the occurrence of a catalytic cycle involving transmetalation of the alkyl zinc halide to Ni(I) followed by oxidative addition of the haloarene and C-C reductive elimination.

We have developed a copper-catalyzed substitution reaction of propargylic ammonium salts with aryl Grignard reagents. The reaction is stereospecific and α-regioselective and proceeds with exceptional functional group tolerance. Conveniently, a stable, inexpensive, and commercially available copper salt is used and no added ligand is required.