Review on Bench-Stable Nickel(0) Precatalysts Online

Appearing this week in Accounts of Chemical Research, we chronicle our lab’s journey developing air- stable nickel(0) precatalysts through organometallic investigations of electron-deficient diene (EDD) ligands. This long-standing collaboration between our lab and chemists at Bristol Myers Squibb has yielded several commercially available precatalysts that are widely used in industry and academia. Congrats to the authors, Camille, Wen-Ji, and Steve (from BMS), and thanks to all of the coworkers over the years whose contributions are featured in this article.

For a link to the article, click here: https://pubs.acs.org/doi/10.1021/acs.accounts.3c00638

Decarboxylative Arylation to Prepare Quarternary Centers – Collaborative Study Now in Press at Angewandte Chemie

Today, our collaborative study with the Baran lab and colleagues from Bristol Myers Squibb, Biogen, Leo Pharma, and Enamine describing a new nickel/electrocatalytic decarboxylative arylation method to access quaternary centers appeared online in Angewandte Chemie, International Edition. The method uses a unique combination of pyridine and BINAP as ligands to enable an otherwise challenging coupling event. Camille from our lab contributed to elucidating the complex mechanism of this process. We had a blast collaborating with the team on this creative and useful method!

For a link to the paper in Angewandte Chemie, International Edition, click here: https://onlinelibrary.wiley.com/doi/10.1002/anie.202314617

As a reminder, a ChemRxiv pre-print on this work was uploaded in September 2023: https://chemrxiv.org/engage/chemrxiv/article-details/64f248dddd1a73847ffb6e0d

Happy holidays 2023!

We kicked off the holiday season in style with good food, mulled wine, and our customary white elephant gift exchange. Stuffed animals and holiday-themed mugs were among the hot items for which competition was fierce. It’s been a year of transition, with several group members taking the next steps in their education/career and many new member joining, and throughout it all we’ve had a lot of fun in and outside of the lab. Here’s to another wonderful year to come!

Amit completes his postdoc

After two awesome years in San Diego, we bid farewell to Amit who is headed back to India to begin his independent career in the Department of Chemical Sciences at IISER Berhampur. There was ample reason to celebrate! In addition to his new job, Amit and his wife are also expecting a baby girl in the new year. We gave Amit a send-off at Kate Sessions Memorial Park with good food and fun baby shower games. Thanks for everything and best of luck in your next adventure, Amit!

Electroreductive Synthesis of Diverse Nickel(0) Complexes – Manuscript in Press at Angewandte Chemie

The final version of our manuscript describing an electrochemical method to covert NiII 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

Ligand-Enabled 1,2-Carboamidation of Olefins under Nickel Catalysis

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

S(Alkyl) Carbosulfenylation Reaction Enabled by Ni–Quinone Complexes – Pre-Print Now Online

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

Atroposelective C–H Activation of Heteroarenes to Establish Chiral C–N Axes – Pre-Print Now Online

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

Pumpking Carving Party!

The lab had a blast gathering together to eat good food, carve pumpkins, and enjoy the beautiful October weather. Props to everyone for amazing designs and technical skill, especially all of the first-time carvers. Happy Halloween!

Azaheterocycle-Directed 1,2-Diarylation of Alkenes – Manuscript In Press

The latest installment of our research on directed 1,2-diarylation of alkenes under nickel catalysis appears online this week in Tetrahedron Letters. In this study, Yilin and Zi-Qi demonstrate that structurally diverse five-membered azaheterocycles can efficiently direct nickel-catalyzed 1,2-diarylation of proximal alkenes under simple and user-friendly reaction conditions. The method offers a quick route to 1,2,4-tri(hetero)aryl alkanes that are otherwise difficult to access. The manuscript is part of a special virtual issue honoring Prof. Bill Morandi, recipient of the 2023 Tetrahedron Young Investigator Award.

For a link to the paper, click here: https://www.sciencedirect.com/science/article/pii/S0040403923004744