Our next webinar will take place via the internet on Tuesday November 9th at 8 PM EST/ 1 AM GMT. Sign up on our mailing list to receive the Zoom link!
We hope to see/hear from you all at one of our sessions or as one of the next speakers. If you are an early career scientist and would like to present your research, don't hesitate to submit an abstract today! For now, please learn more about our current speakers and their research below. We also thank the generous support from Cell Reports Physical Science, Merck, and the Royal Society of Chemistry.
Our featured speakers this week are Stanna Dorn (graduate student, Indiana University, USA), and Dr Tristan Clemons (assistant professor, University of Southern Mississippi, USA).
LEARN MORE ABOUT THE SPEAKERS AND THEIR TALKS BELOW
STANNA DORN (on Twitter @stannadorn)
Biography: Stanna is from Grayling, MI. She graduated with a B.S. in Chemistry and a B.A. in Music from Hope College in 2017, where she performed organometallic research investigating Rh-catalyzed C-C bond activation under the guidance of Prof. Jeffrey B. Johnson. After a summer stint in Prof. John Montgomery’s lab (University of Michigan) where she made non-native substrates for evaluation in enzymatic oxidation, Stanna knew she wanted to pursue graduate studies in organic chemistry and started at Indiana University-Bloomington to do so. In Prof. Kevin Brown’s lab, Stanna has been working on the difunctionalization of alkenes via Cu/Pd synergistic catalysis, which has included a regiodivergent arylboration of 1,1-disubstituted styrene derivatives and more recently, an alkenylboration method to access valuable double allylation reagents. When she is not in the lab, Stanna enjoys reading, playing the flute, and binge-watching competitive art shows on Netflix.
Title of Talk: Cu/Pd Synergistic Catalysis: Alkenylboration Enables Double-Allylation
Abstract: While a plethora of avenues exist to achieve molecular complexity, alkene difunctionalization represents an appealing way to do so owing to the ubiquitous nature of alkenes, their simplicity as building blocks, and their cost. Over the years, our group has established Cu/Pd synergistic catalysis in a variety of contexts for alkene functionalization as a way to access more complex scaffolds; much of this work has been devoted to stereoselective arylboration of styrene derivatives and various acyclic diene classes. However, much remains to be developed in this area, including broadening the alkene substrate classes that are competent with this chemistry and its overall synthetic utility. To address this, we recently disclosed a Cu/Pd-alkenylboration of alkenylboronamide derivatives in order to access Type III double-allylation reagents. After completing the double-allylation sequence, these reagents provide complex 1,4-diol scaffolds in a highly diastereoselective manner. Notable aspects of this method include 1) a broad alkenylboration substrate scope that includes di-, tri-, and tetra-substituted vinylhalide electrophiles; 2) the alkenylboration can be done in a diastereoselective, enantioselective, and stereodivergent manner, providing a variety valuable allylation precursors; 3) novel use of an allylboronamide directly in a stereocontrolled allylation without initial deprotection to the boronic ester; and 4) a stereocontrolled second allylation to access complex 1,4-diol motifs with multiple contiguous stereocenters. Additionally, a preliminary mechanistic analysis was undertaken in order to explore factors leading to stereospecific and non-stereospecific reactivity. Overall, the modularity and the ease in which complex structural motifs can be accessed in a rapid manner signify the importance and utility of this method.
DR TRISTAN CLEMONS (on Twitter @clemo_11)
Biography: Tristan Clemons started his research journey in Australia with a PhD and Australian Biomedical Research Fellowship at the University of Western Australia. In 2018, he relocated to Chicago to join the laboratory of Prof. Samuel Stupp at Northwestern University as a post-doctoral research fellow. This fall Tristan started as an Assistant Professor within the School of Polymer Science and Engineering at the University of Southern Mississippi, to find out more about his work and the future of the Clemons Lab you can visit his website at www.clemonslab.com.
Title of Talk: Smart supramolecular polymers for 3D printing and regenerative medicine applications
Abstract: Reversible hierarchical self-assembly of molecules, have been harnessed by living systems to control the formation of structures such as protein assemblies, cellular membranes, cytoskeletal filaments along with many others. By controlling multiple orthogonal interactions between molecules, we design supramolecular systems that mimic these reversible hierarchical processes. I will present on a supramolecular system in which exchange dynamics and host-guest interactions between 𝛽-cyclodextrin- and adamantane-functionalized peptide amphiphiles led to reversible superstructure formation. The host-guest interaction between the 𝛽-cyclodextrin and adamantane resulted in the generation of bundled nanoribbons to create a mechanically robust hydrogel with a highly porous architecture suitable for 3D printing. Functionalization of the porous superstructured material with a biological signal results in a matrix with enhanced neuronal infiltration and significant in vitro bioactivity. These reversible hierarchical bioactive superstructures overcome the challenges of printing sensitive cell types while allowing the fabrication of complex brain tissue-like architectures. The combined benefit of bioactive chemical signaling, hierarchical superstructure formation, coupled with the ability to print self-supporting cell-laden hydrogels make this an exciting biomaterial for tissue regeneration applications.
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