Congratulations to rising G4 student Luke Oxtoby who has been awarded the 2021 International Precious Metals Institute Johnson Matthey Student Award in recognition of his graduate research, where he has achieve the first successful examples of enantioselective Heck-type alkene additions using a transient directing group strategy. Luke will travel to the IPMI annual conference in Reno, Nevada, in October, where he will present his research at a special awards session.
We have a new undergraduate intern Yilin, from UCSB. She has explored nickel-catalysis in aqueous micellar conditions as an undergraduate research assistant in Prof. Lipshutz’s group, and now she will be expanding her experience in nicekl catalysis, joining the Team Nickel under the mentorship of Ziqi.
Time flies when you’re having fun, living through a pandemic, or both! The Engle lab celebrated six wonderful years at Scripps with an afternoon at the beach in Del Mar, where we enjoyed surfing, frisbee, and BBQ. The event doubled as a welcome party for our two newest members, José and Yilin. After more than a year of virtual social events, it was a special treat to gather together and celebrate this milestone.
Over the years we’ve experienced first-hand the frustrations of resorting to circuitous synthetic routes to access substituted alkenyl AQ amide substrates, which serve as cornerstones of AQ-directed alkene functionalization chemistry. To address this Hui-Qi, Zi-Qi, and Van teamed up to develop a concise and modular method using cross-metathesis with the Grubbs 2nd generation catalyst. Remarkably the catalyst is impervious to the AQ group, allowing direct coupling of terminal alkenyl AQ amides with a variety of terminal alkenes. In one case, we shorten a four-step sequence to a single high-yielding step. This paper is part of a special issue in Tetrahedron celebrating Prof. Guangbin Dong’s2021 Tetrahedron Young Investigator Award. Well done team!
We have a summer visiting gradudate student José González from Gulías group at CIQUS-USC, Spain. He has been working on enantioselective Pd-catalyzed C-H activation at Gulías group. In the Engle lab, he is turning his attention to Ni-catalysis, collaborating with Taeho.
On a whirlwind of a day, Andrew successfully defended his thesis over Zoom, dropped by campus for his champagne toast, and then hit the road for the transcontinental drive back to his hometown of Philadelphia. Starting next week, Andrew will begin his career as a consultant at Boston Consulting Group. We’re so grateful for your many contributions to the lab and proud of your accomplishments, Andrew. Good luck on this next adventure!
The final version of our manuscript describing the palladium-catlayzed enantioselective 1,2-arylfluorination of alkenes using a transient directing group (TDG) strategy is online today in J. Am. Chem. Soc. In the study we apply Design of Experiments (DoE) to optimize this challenging three-component coupling of alkenes, arylboronic acids, and [F+] electrophiles, which helps to account for the complex interactions between variables in this system. We further elucidate the reaction mechanism using reaction progress kinetic analysis (RPKA). In terms of preparative applications, the method proceeds in high ee and d.r., allowing formation of full substituted C(sp3)–Ar and C(sp3)–F centers. The transformation is the first time that 1,2-difunctionalization has been achieved using a TDG approach and as such represents an important milestone for our lab and for the field. Hats off to Zhonglin, Luke, Mingyu, Zi-Qi, Van, and Yang!
With the lab fully vaccinated we were very happy to be able to give Dr. Van Tran a proper send off, including a Korean BBQ trip and a champagne toast. Best of luck in your next adventure as a process chemist at Gilead, Van! We miss you already.
In a pre-print appearing today on ChemRxiv, we provide a full account of our efforts to develop substrate-directed Markovnikov-selective hydroarylation/alkenylation of terminal alkenes with organoboronic acids under nickel(0) catalysis. In the paper, we tackle three important substrate classes, alkenyl sulfonamides, ketones, and amides, and discuss the systematic tuning of reaction conditions that is required to provide high yields in each case, reflecting subtle yet significant differences in coordination chemistry among the directing groups involved. Through a combination of isotope labeling, reaction kinetics, and density functional theory (DFT) calculations, we identified transmetalation as the turnover-limiting and selectivity-controlling step. Congrats to Zi-Qi, Omar, and Ruohan on this herculean effort.
It has been a long time since we’ve been able to enjoy a group outing! This weekend, we did just that. We headed up to the Carlsbad Strawberry Company to get our fill of sunshine and fresh strawberries.