Over the past two years our lab and other labs around the world have been working hard to develop strategies for controlling enantioselectivity in palladium-catalyzed directed hydrofunctionalization and 1,2-difunctionalization reactions. Last month, we described a Pd(II)/chiral phosphoric acid system for enantioselective hydrofunctionalization with prochiral nucleophiles (click here). In a manuscript appearing online today in ACS Catalysis, we describe a new method for enantioselective anti-carboboration, representing the first time that a 1,2-difunctionalization within this family of reactions has been rendered enantioselectivity (click here). We also propose a new mechanistic model based on stoichiometric experiments to account for the stereoconvergent nature of the transformation. Congrats to all of the authors, Zhen, Xiaohan, and Tian (May). Special props to our two undergrad co-authors, Xiaohan and May! In case anyone missed it, a pre-print of this work was published on ChemRxiv back in early January (click here).

Lea starts her visiting masters program from Freie Universität, Berlin! She wasted no time in starting work in the hood, setting up some reactions with mentor Andrew (G3)!

After a fun and productive six months in San Diego, Tianhua (Josh) Tang, finished his internship and now returns to Nankai University in Tianjin, China, to write his undergraduate thesis before graduating this spring. After earning his Bachelor’s degree, Josh will return to the US pursue his Ph.D. in organic chemistry (location TBD). During his time in the Engle lab, Josh worked under the mentorship of Mingyu and made significant contributions to the development of new catalytic alkyne functionalization methods. Outside of the lab, he enjoyed learning about American culture from his many friends in the lab and sampling the myriad restaurants in San Diego, including the various Chinese restaurants in Kearny Mesa.

The Engle lab bids farewell to our superstar visiting Master’s student Roman Kleinmans, who will now return to WWU Münster to pursue his Ph.D. studies with Prof. Frank Glorius. Roman was a valued member of Team Nickel, and made important contributions to advancing new methods for conjunctive alkene cross-coupling directed by simple functional groups. When he wasn’t in the lab, Roman learned how to surf, took a California road trip, and made many great friends in- and outside of Scripps. Props to Joe for great mentorship throughout Roman’s stay in San Diego. We will miss you, Roman! Best of luck in your Ph.D.

Congrats to Keary and the entire Engle Lab for being selected as a 2019 Alfred P. Sloan Fellow! This award recognizes, “distinguished performance and a unique potential to make a substantial contribution to (the field of chemistry).” This honor is a testament to the hard work and creativity of all group members, past and present, over the past four years. Way to go!

https://sloan.org/fellowships/

For the past two years the Engle lab has been hard at work developing effective strategies to control enantioselectivity in catalytic directed alkene hydrofunctionalization and 1,2-difunctionalization. Today, a new method for enantioselective α-alkylation of azlactones with non-conjugated alkenes via Pd(II)/chiral phosphoric acid catalysis was accepted for publication in Angew. Chem. Int. Ed. (click here). This unique transformation enables preparation of highly functionalized quaternary α-amino acids. In collaboration with Prof. Peng Liu, we performed a series of detailed experimental and computational studies to elucidate a viable model to explain stereoinduction in which the CPA plays the dual role of coordinating to the incoming carbon nucleophile during reversible carbopalladation and then serving as a proton transfer mediator in the turnover-limiting protodepalladation step. Congrats to all of the authors from the Engle lab—Sri, Mingyu, Malkanthi, De-Wei, and Omar! Thanks too to Prof. Liu and Dr. Jason Chen from the Automated Synthesis facility at Scripps Research. In case anyone missed it, a pre-print of this work was published on ChemRxiv back in early November (click here).

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Congrats to superstar G3 student and Van Tran on being selected for the 2019 WCC/Merck Research Award. The WCC/Merck award recognizes 8 outstanding female scientists across the country and provides them with the opportunity to present their research along with fellow awardees at a special session at the Fall ACS Meeting in San Diego. In the Engle lab, Van’s research has focused on nickel-catalyzed conjunctive cross coupling (J. Am. Chem. Soc. 2017, 139, 10657) and on palladium-catalyzed strong-bond activation via β-X elimination (Nat. Chem. 2018, 10, 1126). Outside of the lab, Van serves as Advocacy Co-Chair for the Scripps Network for Women in Science (NWiS). Thanks to Merck for the their support, and way to go Van!

Xiaohan finishes her six-month internship this week, just in time to return home to spend Chinese New Year with her family. Xiaohan gave an awesome wrap-up talk describing her work on enantioselective directed carboboration of alkenes, and then the lab sent her off in style with a celebratory Korean BBQ lunch. Xiaohan will receive her Bachelor’s degree in chemistry this spring from Nankai University, and she will then return to the US next fall to begin her PhD (exact location still TBD). Thanks for all of your contributions to the lab, Xiaohan! We will miss you!

Today we report our first foray into the enantioselective 1,2-difunctionalization of alkenes, with a new method for palladium(II)-catalyzed asymmetric anti-carboboration. The reaction is promoted by a palladium(II) catalyst and a mono-dentate oxazoline (MOX) ligand. This reaction was found to be stereoconvergent, with both E- and Z-configured alkenes giving the same major diastereomer. Mechanistic studies were performed to shed light on the origin of this phenomenon. A pre-print of this work is available on ChemRxiv (click here). Congrats to the authors, Zhen, Xiaohan, and May, particularly our two undergraduate co-authors Xiaohan and May.

It’s the season of giving and what better way to celebrate the holidays than with non stop outreach opportunities! First, we had the boss young scientists of BEWiSE hosted by Fleet Science come learn about organometallics. Then students from the distant lands of Palm Springs came to help us set things on fire. (This time no evacuation!)