1,2-Carbofluorination of unactivated alkenes enabled by a sterically tuned auxiliary design – Pre-print now online

In the latest story arising from our lab’s Bristol Myers Squibb collaboration, we report the design of a sterically tuned directing auxiliary, picolinyl-α,α-gem-diethyl amine (PDE), which promotes C(sp3)–F reductive elimination from a Pd(IV) intermediate and enables efficient syn-1,2-carbofluorination of unactivated alkenes under Pd(II)/Pd(IV) catalysis. The improved yield of PDE versus classical directing auxiliaries, such as 8-aminoquinoline (AQ) and 2-(pyridin-2-yl)isopropyl (PIP) is rationalized by comparison of % buried volume (%VBur) across the three pre-reductive-elimination intermediates. Great work by Zhonglin, Luke, Zi-Qi, and Nana on the Scripps side and Geraint from BMS Discovery Chemistry.

For a link to the pre-print in ChemRxiv, click here: https://chemrxiv.org/engage/chemrxiv/article-details/62608592d048ed03304b657d

Selective C(alkenyl)–H Activation Enabled by a Transient Directing Group – Manuscript In Press in Angew. Chem. Int. Ed.

The final version of our collaborative study with the laboratory of Prof. Peng Liu on site-selective palladium(II)-catalyzed C(alkenyl)–H activation enabled by a transient directing group (TDG) appears online today in Angewandte Chemie International Edition. This project continues our research program in developing alkene functionalization reactions that take advantage of reversible attachment of a catalytic mediator (i.e., a TDG). In this work, we show that the presence of a tailored carboxylic acid co-catalyst in conjunction with an amino acid TDG enables C(alkenyl)–H activtion via an exo-palladacycle intermediate. We develop an atropselective method that enables access to axially chiral substituted 1,3-dienes, synthesize alkenyl palladacycle model complexes, and examine the reaction mechanism through DFT. Congrats to Mingyu, Juntao, Tugce, Hui-Qi, and Raul for a great paper!

For a link to the paper, click here: https://onlinelibrary.wiley.com/doi/10.1002/anie.202203624

As a reminder, a pre-print of the paper was deposited in ChemRxiv in March: https://chemrxiv.org/engage/chemrxiv/article-details/622412c997f2109450fec97a

Skyler is awarded an NSF MPS-Acsend Postdoc Fellowship

Congrats to Dr. Skyler Mendoza who has received a National Science Foundation Mathematical and Physical Sciences Ascending Postdoctoral Research Fellowship (NSF MPS-Ascend) to support his work developing dual catalytic fragment insertion methods as well as various outreach activities in San Diego County. Prior to joining the Engle lab in November 2021, Skyler received his Ph.D. from Caltech, where his research in the lab of Prof. Sarah Reisman focused on natural products total synthesis and synthetic methods development. Congrats Skyler!

To learn more about the NSF MPS-Ascend Postdoc Fellowship, click here: https://beta.nsf.gov/funding/opportunities/mathematical-and-physical-sciences-ascending-postdoctoral-research

Catalytic syn-Carbosulfenylation Paper Published in J. Am. Chem. Soc.

The final version of our paper describing Ni(I)/Ni(III)-catalyzed carbosulfenylation is online today in the Journal of the American Chemical Society. The method allows conversion of a diverse collection of widely available alkenes bearing native directing groups to structurally complex organosulfide products, with reactivity and selectivity emanating from specially tailored N–S electrophiles. The syn-stereoselectivity of the reaction complements classical thiiranium chemistry, which delivers anti-sulfenylfunctionalized products. Congrats to graduate students Zi-Qi and Taeho and former SURF intern Yilin. Great work!

For a link to the paper in J. Am. Chem. Soc., click here: https://pubs.acs.org/doi/full/10.1021/jacs.1c13252

As a reminder, a pre-print of the paper was first deposited back in December 2021: https://chemrxiv.org/engage/chemrxiv/article-details/61a7d3e0f35d4ca9794de71d

Zi-Qi Li is selected for 2022 Corteva Agriscience Chemistry Scholars Symposium

Congrats to G4 student Zi-Qi Li, who has been selected to participate in the inaugural Corteva Agriscience Chemistry Scholars Symposium to be held at Corteva’s Global Headquarters in Indianapolis, IN on May 11-13th, 2022! During the symposium, Zi-Qi and other awardees will present their research, tour Corteva’s facilities, and learn about industrial R&D in the agricultural chemistry industry.

Current and Former Engle Lab Students Recognized by National Science Foundation

Hearty congratulations to three outstanding young chemists from the Engle lab, who were acknowledged by the National Science Foundation Graduate Research Fellowship Program:

• Pranali Bedekar, UCSD undergrad intern (2019–present), starting in the Ph.D. program at Scripps Research this fall
– awarded Graduate Research Fellowship

• Hanh Nguyen, UCSD undergrad intern (2018–2019), currently enrolled in the Ph.D. program at UC Irvine with Prof. Chris Vanderwal
– awarded Graduate Research Fellowship

• Camille Rubel, current TSRI grad student and Engle lab member (2020–present)
– acknowledged with Honorable Mention

Wen-Ji and Jing-Cheng complete their undergrad internships

Our superstar visiting undergrads Wen-Ji He and Jing-Cheng Dai have completed their internships , and will now return to their home institutions, Nankai University and USTC, respectively, to complete their undergrad degree requirements. We are grateful for their hard work and dedicating over the past several months, and we can’t wait to see what these two will accomplish during the PhDs. Wen-Ji will return to Scripps Research, and Jing-Cheng will be heading to UW Madison. Thanks to Zi-Qi and Hui-Qi for great mentorship throughout the internship period.

Drs. Yeongyu Hwang and Johny Nguyen join the group as postdocs

The Engle lab is pleased to welcome two new postdocs, Drs. Yeongyu Hwang and Johny Nguyen, who start in the lab this week.

Yeongyu completed his Ph.D. at KAIST with Prof. Sukbok Chang, where his research focused on iridium-mediated nitrene transfer reactions enabled by innovative catalyst design.

Johny completed his Ph.D. at Vanderbilt with Prof. Steve Townsend, where his research focused on the synthesis and biological investigation of zwitterionic polysaccharides.

We look forward to working with these two and seeing what exciting science they pursue in the Engle lab over the coming years!