Metal-catalyzed C–C bond forming reactions have streamlined synthetic routes when assembling complex molecules. These methods are particularly important when incorporating unreactive saturated hydrocarbons, which are common motifs in petrochemicals and biologically relevant molecules. Recently, nickel-catalyzed reductive cross-coupling reactions have become a powerful alternative to traditional cross-coupling reactions for the formation of C–C bonds. Apart from the operational simplicity of these procedures, the wide commercial availability of electrophiles as compare to organometallic reagents, and the highly chemo-selectivity derived from the in-situ formation of transient organometallic species, make cross-electrophile coupling high attractive to synthetic chemists.

In line with our group interests in Ni-catalyzed cross-coupling reactions, we have decided to focus my doctoral studies on the development of sp3 C–C bond forming reactions by means of nickel-catalyzed reductive cross-coupling.

Our first efforts were focused on the development of reductive alkylation of a-haloboronates with unactivated olefin feedstocks. Towards this goal, we developed a mild, chemo- and site-selective catalytic protocol that allows for incorporating an alkylboron fragment into unactivated olefins. The use of internal olefins enables C−C bond-formation at remote sp3 C−H sites via nickel-catalyzed chain-walking process. Of particular importance was the ability to establish a platform to build up multiple sp3–sp3 bonds in an iterative fashion from simple building blocks.

Following this development of nickel-catalyzed chain-walking process, we reported a site-selective catalytic deaminative alkylation of unactivated olefins that operates under mild conditions and is characterized by its wide substrate scope and

exquisite site-selectivity profile. Particularly noteworthy is that this technique could also be employed in the context of ethylene derivatization and late-stage functionalization. This new platform offers new opportunities in both olefin functionalization and sp3 C–N bond cleavage events and a complementary activation mode to existing sp3–sp3 bond-forming events.

Our final efforts on sp3 C–C bond formation were focused on the development of a regio-selective three electrophile cross-coupling by means of nickel/photoredox dual catalysis. In this work, we were able to developed a modular, chemo- and regio-selective 1,2-difunctionalization of simple vinyl boronates with readily available organic halides through a dual catalytic platform. In a formal sense, our method serves as a testament to the viability of conducting a reductive cross-couplings of three different electrophilic partners in a synergistic manner.

In conclusion, we have developed new methods for the construction of new sp3 C–C bonds via nickel catalysis or nickel/photoredox dual catalysis under exceptionally mild conditions and with excellent chemo- and regio-selectivity profiles.

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