The final version of our manuscript describing an electrochemical method to covert Ni^II salts into various synthetically useful Ni⁰ complexes appears today in Angewandte Chemie International Edition. Through systematic optimization of reaction parameters, we developed a method that avoids traditional stoichiometric organometallic reductants, such as DIBAL–H, that are commonly employed in this process. The method is robust, scalable via a recirculating flow setup, and applicable to numerous important products (e.g., Ni(COD)₂, Ni(COD)(DQ), and Ni(PP₃)₄). Congrats to the entire collaborative team, including Camille and Yilin from our lab, Tamara and Gabriele from the Baran lab at Scripps, Greg and Steve from Bristol Myers Squibb, Xiangyu from the Lin lab at Cornell, and Julien from Syngenta/University of Lyon.

For a link to the paper in Angew. Chem. Int. Ed., click here: https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202311557

As a reminder, a ChemRxiv pre-print disclosing this work first appeared back in April: https://chemrxiv.org/engage/chemrxiv/article-details/642b6699a029a26b4cde3e3e

Appearing today in J. Am. Chem. Soc., Yeongyu describes our latest work on Ni(quinone) precatalysts. Building on similar themes to Zi-Qi’s preprint on 1,2-carbosulfenylation from last week, we find that the hemilabile nature of quinone ligands allows them to exhibit different coordination modes to the metal center during the catalytic cycle to tune steric and electronic properties. During the migratory insertion step, the carbonyl-bound state enhances the electrophilicty of the organonickel species, lowering the energy barrier. Yeongyu teased out these mechanistic nuances through a series of experiments and DFT calculations. From a simple computational model, he was then able to design new catalyst that offer superb product yield and substrate scope. This study grew out of a longstanding collaboration with Bristol Myers Squibb, particularly Dr. Steve Wisniewski.

For a link to the paper in J. Am. Chem. Soc., click here: https://pubs.acs.org/doi/10.1021/jacs.3c08855

In the first of a two-paper installment (stay tuned for the second!), we document how the unique hemilabile and redox-active properties of quinone ligands can enable otherwise challenging nickel-catalyzed alkene functionalization reactions. In particular, we show dramatic ligand-enabled expansion of the scope of our previously developed syn-1,2-carbosulfenylation reaction of unactivated alkenes to include a variety of N–S(Alkyl) electrophiles and alkyl- and alkenylboron nucleophiles that were previously recalcitrant. Important mechanistic insights from DFT and structural characterization came through the awesome collaboration with Turki (University of Pittsburgh) and Matt (Bristol Myers Squibb), shed light on the hemilabile and redox-active nature of the ligand in the catalytic cycle. We expect that this mechanistic framework should pave the way for numerous advances in the future. Congrats to project lead Zi-Qi and the entire team!

For a link to the pre-print in ChemRxiv, click here: https://chemrxiv.org/engage/chemrxiv/article-details/6544308648dad23120f59b66

In our latest ChemRxiv pre-print we describe a unique atroposelective C(Heteroaryl)–H olefination process the establishes a chiral C–N axis under dual catalysis of Pd(II) and an amino acid transient directing group. Included in the scope are four classes of “enamine-type” azaheterocycle, which all proceed with high levels of enantioselectivity. The diene-type character of the C–H olefinated heterocycles can be leveraged in downstream Diels–Alder [4+2] cycloaddition, granting access to densely functionalized sp³-rich C–N atropisomers. Congrats to the team on this advancement!

For a link to the pre-print in ChemRxiv, click here: https://chemrxiv.org/engage/chemrxiv/article-details/6541721bc573f893f1889f75