CuH-Catalyzed Cascade Hydrofuntionalization Paper – Now In Press

Appearing online this week in Nature Catalysis, our De-Wei, Yang, and team describe an unusual CuH-catalyzed cascade reaction to transform terminal alkynes into enaptioenriched 1,1-aminoboron compounds in a single step. In addition to synthetic applications of this remarkable transformation, we examined its mechanistic underpinnings to understand the origins of reactivity and selectivity. Thanks to Huiling from Prof. Peng Liu’s group at the University of Pittsburgh for a great collaboration and our colleagues Jason and Brittany from the Automated Synthesis Facility at Scripps Research. In case anyone missed it, a pre-print of this work was deposited in ChemRxiv back in April (click here).

Click here for a link to the paper: https://www.nature.com/articles/s41929-019-0384-6

Review Article on Pd/CPA Dual Catalysis – Just Accepted

Congrats to Van, Sri, and Mingyu, whose review article entitled, “Recent Applications of Chiral Phosphoric Acids in Palladium Catalysis,” has been accepted for publication in Org. Biomol. Chem. The article provides an overview of key reaction classes as well as different modes of co-catalysis that have emerged in this area during the past decade.

For a link to the paper, click here: https://pubs.rsc.org/en/content/articlelanding/2019/ob/c9ob02205h#!divAbstract

Nickel-Catalyzed 1,2-Diarylation of Alkenyl Carboxylates – Now Accepted

For the past few years, our group has developed a toolkit of catalytic alkene 1,2-difunctionalization reactions using a substrate directivity strategy. Our early work employed bi- and tridentate auxiliaries for this purpose, which have proven to be highly effective and generally useful. Recently, in an exciting series of studies, we have found that simple functional groups are also capable of directing nickel-catalyzed 1,2-diarylation. In the present paper, as part of our ongoing collaboration with Bristol-Myers Squibb, Joe, Taeho, Van, Steve (from BMS Process Chemistry), Malkanthi, Tanner, and Kane describe the use of simple carboxylic acids as competent directing groups for alkene functionalization. After 1,2-diarylation, we can take advantage of classical and modern carboxylic acid functional group interconversions to access a myriad of 1,2,3-trifunctinoalized core structures. Nice work to all of the authors, and special congratulations to our former high school intern Kane, for publishing his first paper!

For a link to the paper, click here: https://onlinelibrary.wiley.com/doi/abs/10.1002/ange.201913062

BCP Hydroboration Paper – Now In Press

Our most recent collaboration with Pfizer and the Liu group at the University of Pittsburgh is now in press at ACS Catalysis. Methods to access small carbo- and heterocycles are of special importance in modern pre-clinical drug discovery and development owing the special properties of such motifs (conformationally restricted, low lipophilicity, etc.). In this project we developed a method to access substituted cyclopropyl boronic esters from benzylidene cyclopropanes (BCPs), which in turn can be made in a single step from benzaldehydes. While optimizing the reaction, we discovered an interesting effect of the ligand structure on pathway selectivity, and ultimately identified one ligand (BINAP) that could give almost exclusively ring-closed products, and another (dppe) that could give almost exclusively ring-opened products. To shed light on this phenomenon, our collaborators in the Liu group built a computational model that explains the observed reactivity trends. In terms of practical utility, we found the reaction to be compatible with a wide variety of azaheterocycles that are typically challenging to use in catalysis but are essential for medicinal chemists. Congratulation to all authors, particularly project co-leads Jose and Taeho.

For a link to the paper, click here: https://pubs.acs.org/doi/10.1021/acscatal.9b03557

Directed Nickel-Catalyzed Oxidative Heck Coupling Enables by a Tailored H2 Acceptor

In collaboration with the Xue and Zhao groups from Nankai University, we describe a mechanistically unusual reaction to effect oxidative coupling of alkenes and arylboronic acids under nickel(0) catalysis, appearing today in a manuscript in Nature Communications. Previously, it has been shown that Ni(0) can oxidative add into alcohol O–H bonds to generate a catalytically active Ni(H)(OR), which is capable of mediating hydroarylation of alkenes. Based on careful tuning of the directing group, ligand, and hydrogen acceptor (an electron-poor alkene), we find that this pathway can be perturbed to instead give oxidative Heck products. The reaction is highly regioselective, even with challenging 1,2-disubstituted alkene substrates. Congrats to all of the authors.

For a link to the manuscript, click here: https://www.nature.com/articles/s41467-019-12949-1

Happy Halloween!

Our talented team of students carved some amazing pumpkins at the Engle Lab’s annual Halloween party! It was a spooky time spent playing video games and eating great food!