Alkyne 1,2-Oxyhalogenation In Press at Angewandte Chemie

The final version of our paper describing the directed 1,2-oxyhalogenation of unactivated alkynes appears online today in Angewandte Chemie International Edition. In this investigation, we demonstrate the successful extension of our labs approach for modular three-component π-bond functionalization from alkenes to alkynes. Specifically, we find that the 2-(pyridin-2-yl)isopropyl (PIP) amine directing auxiliary is able to mediated the classically challenging regioselective, three-component oxyhalogenation of internal alkynes, allowing for simple preparation of tetrasubstituted alkenes containing diversifiable functional handles. Congrats to Mingyu, Juntao, and Raul from Scripps, as well as our collaborators from the Lan group and Zhengzhou University and the Shi Lab at Zhejiang University.

For a link to the peer-reviewed paper in Angew. Chem. Int. Ed., click here: https://onlinelibrary.wiley.com/doi/10.1002/anie.202209099

For the initial pre-print that was deposited at the end of June, click here: https://chemrxiv.org/engage/chemrxiv/article-details/62a263752e62696e467d88b5

2022 Padres Home Game!

It has been a long time since we’ve been able to enjoy a group outing! This week, we did just that. We headed downtown to Petco stadium for an awesome Padres home game! It was great welcoming our new class of students and bringing back some old traditions!

GABBY AND ANUSH COMPLETE THEIR SUMMER INTERNSHIPS!

We bid Gabby and Anush farewell! After spending a chemistry-intense summer in the Engle lab, Gabby heads back to CSU San Marcos to complete her final year of coursework! Anush will be returning back home to finish his final year of high school! It was a great joy to hear about their summer accomplishments, in collaboration with Alena and Shenghua. Everyone from the Engle lab is wishing them the best luck in their future endeavors.

Welcome New Members!

To kick off the academic year, we welcome new members Madison Wagner, Yilin Cao, and Wenji He to the Engle lab!

We can’t wait to see all of the wonderful things they’ll do!

Directed alkyne oxyhalogenation pre-print online

Over the years, we’ve found that translating lessons learned in alkene difunctionalization to alkyne substrates is not as straightforwards as it seems, owing to unique reactivity profiles of alkyl- versus alkenylpalladium species. In our most recent collaboration with the Shi group from Zhejiang University and the Lan group from Zhengzhou University, we show that use of the 2-(pyridin-2-yl)isopropyl (PIP) amide directing group enables regio- and stereoselective oxyhalogenation of alkynes. The alkenyl halide products can be readily diversified via cross-coupling to access an array of tetrasubstituted alkene products. Congrats to Mingyu, Juntao, and Raul (Scripps Research); Tao (Zhengzhou U), Yi and Ye-Qiang (Zhejiang U) for an excellent study.

For a link to the ChemRxiv pre-print, click here: https://chemrxiv.org/engage/chemrxiv/article-details/62a263752e62696e467d88b5

Enantioselective three-component 1,2-diarylation and -arylalkenylation of alkenes – Pre-print now online

After >3 years of work, we are happy to share a ChemRxiv pre-print today describing a solution to a longstanding problem, stereoinduction in intermolecular arylnickel migratory insertion into alkenes, which we investigated in the context of interest in catalytic 1,2-dicarbofunctionalization. We found that a sterically bulky, achiral sulfonamide directing group works in synergy with a specially tuned hemilabile ligand (Bn-biOX) to promote high enantioselectivity with a variety of arylboron and aryl iodide coupling partners. Through use of experimental and computational techniques, we elucidated the mechanism of this three-component catalytic coupling, which involves an enantiodetermining migratory insertion step, which is distinct from previous radical-based methods. It was a great collaborative effort between our lab (Omar, Taeho, Pranali, Camille, and Joe), the Liu lab at the University of Pittsburgh (Turki), the Scripps Automated Synthesis Facility (Brittany, Quynh, Emily, and Jason), and Bristol Myers Squibb (Steve). Congrats to everyone!

For a link to the pre-print in ChemRxiv, click here: https://chemrxiv.org/engage/chemrxiv/article-details/62b40edc0bbbc1d407726e34

International Precious Metals Institute Recognizes Alena

Congrats to rising G5 student Alena Vasquez who was awarded a 2022 IPMI Student Award by the International Precious Metals Institute, which was presented this week at the IPMI Conference in Orlando, FL. Alena was recognized for her pioneering work in developing a novel approach to palladium-catalyzed alkene hydrofunctionalization by harnessing trans-Pd(Ar)(H) intermediates. Along with Alena’s recognition, during the program Keary was acknowledged with the 2022 IPMI Advisor Award. Congrats!

For more about the IPMI Student Awards program, click here: https://www.ipmi.org/page/AwardPrograms

Welcome Gabby and Canyon!

Gabby, a rising Senior at CSU San Marcos, arrives for her summer internship in the Engle lab as part of the SURF program. She is excited to explore the world of transition metal catalysis with her mentor Alena! Canyon, a rising high school Senior from Ridgway Secondary School in Colorado, kicks off his summer research internship in the Engle lab with his mentor Johny! He’s wasted no time in getting his gloves dirty! We’re excited to teach them all about organometallics!

Transient Directing Group Strategy Expanded to Enantioselective Hydroalkenylation and Hydroalkynylation – Pre-Print Now Online

In a pre-print appearing online today in ChemRxiv we introduce new families of coupling partners and alkenyl aldehyde substrates into the dual catalytic platform using a transient directing group (TDG) as an organocatalyst together with palladium as the redox catalyst. Specifically, we show that under specifically tailored conditions, alkenyl and alkynyl bromides can engage in enantioselective reductive Heck hydrofunctionalization with ortho-alkenylbenzaldehydes, dienyl aldehydes, and non-conjugated aldehydes, establishing a new C(sp3)–C stereocenter at the δ position with respect to the aldehyde. Strategic use of Design of Experiment (DoE) again facilitated rapid reaction optimization due to the mechanistic complexity of this dual catalytic process. Congrats to the project team, Amit, Johny, and Luke, Quynh, and Jason! Well done all!

For a link to the pre-print in ChemRxiv, see: https://chemrxiv.org/engage/chemrxiv/article-details/62a521fa2e6269ab067ff2d9