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She received the Ludwig Ramberg Dissertation Prize 2024

Ester Maria Di Tommaso from the Department of Organic Chemistry, Stockholm University, has been awarded with the Ludwig Ramberg Dissertation Prize 2024 for her dissertation Synthetic and Mechanistic Studies on Hypervalent Iodine Reagents.

Can you please describe your research? What is the topic of your dissertation?

– My research focuses on the development of metal-free transformations and the mechanistic investigation of two significant classes of hypervalent iodine reagents: diaryliodonium salts and vinylbenziodoxolones (VBX). My dissertation aims to enhance the understanding and application of these compounds in organic synthesis.

– Hypervalent iodine reagents have emerged as valuable synthetic tools due to their broad applicability, non-toxic nature, and potential as sustainable alternatives to heavy metals. In my work, I explored the synthesis and reactivity of azobenzene-derived diaryliodonium salts, employing these novel reagents in chemoselective arylation reactions with a wide range of nucleophiles under mild, metal-free conditions. I also developed a mild and transition metal-free vinylation method for thiols and mercapto heterocycles using VBX reagents, achieving complete chemo-, regio-, and stereoselectivity in the resulting S-vinylated products. Furthermore, I conducted the first mechanistic investigation of VBX vinylations. Using NMR analysis, deuterium labeling, and density functional theory (DFT) calculations, I was able to rationalize the observed regio- and stereochemical outcomes of these reactions with sulfur and phosphorus nucleophiles. This mechanistic understanding is crucial for predicting the reactivity of VBX reagents with other nucleophiles. Additionally, my research includes the development of a transition metal-free, photocatalyzed C-vinylation method using VBX reagents. This method operates under mild conditions and tolerates a variety of functional groups, providing straightforward access to alkenes with high yields and stereoselectivity.

– Apart from the primary focus of my thesis, I have also worked on other types of arylation reactions, such as the difunctionalization of sulfur nucleophiles, performing extensive DFT studies to elucidate the underlying mechanisms, further contributing to our understanding of these complex reactions. Overall, my dissertation not only advances the field of hypervalent iodine chemistry but also demonstrates the practical and sustainable applications of these reagents in organic synthesis. My work has provided valuable insights into the reactivity and mechanisms of these compounds, paving the way for future developments in the field.

My dissertation not only advances the field of hypervalent iodine chemistry but also demonstrates the practical and sustainable applications of these reagents in organic synthesis.

What are you most proud of with your research?

– What I am most proud of from my PhD journey is the breadth of achievements and personal growth I have experienced. My work not only resulted in publications in high-impact journals, a significant accomplishment in itself, but it also helped me to develop a strong sense of independence and confidence in my abilities to tackle various research projects. Throughout my PhD, I mastered a wide array of techniques, ranging from synthetic methods to advanced mechanistic studies. These skills were crucial in the development of novel, metal-free methodologies using hypervalent iodine reagents, and they also proved essential in other fields of chemistry I explored, such as photoredox catalysis, both within and outside my research group.

– Moreover, I had the privilege of collaborating with experts from different fields, which immensely enriched my research. These collaborations provided me with diverse perspectives and insights, enhancing the quality and impact of my work. Working closely with these experts not only improved my technical skills but also taught me the importance of interdisciplinary approaches in solving complex scientific problems. I am also proud of the professional relationships I built during my PhD. These connections have been instrumental in fostering a collaborative and supportive research environment, enabling me to thrive and push the boundaries of my work. The ability to work independently while effectively collaborating with others is a skill that I will carry forward in my career. Overall, the combination of achieving significant research milestones, developing a versatile skill set, and building a network of esteemed colleagues has made my PhD journey incredibly fulfilling and rewarding. These accomplishments have laid a strong foundation for my future endeavors in the scientific community.

What is your academic background?

– My academic journey began in Italy, where I earned a bachelor’s degree in Chemistry from the University of Parma. During my bachelor’s thesis, I worked under the supervision of Professor Alessandro Casnati working the field of supramolecular chemistry, specifically in synthesizing a Calix[4]arene bifunctionalized model for artificial phosphodiesterase.

After completing her bachelor’s degree, Ester Maria pursued a master’s degree in Industrial Chemistry at the University of Parma, focusing on organic chemistry.

– During this period, I developed a growing interest in computational chemistry, which led me to undertake my master’s thesis as an Erasmus student at King’s College London under the supervision of Professor Edina Rosta. There, I deepened my understanding of density functional theory (DFT) through research on Cucurbit[7]uril (CB[7]) as a supramolecular artificial enzyme for the Diels-Alder reaction. These experiences provided me with a robust foundation in both experimental and computational chemistry, shaping my research approach. In 2018, I embarked on my PhD in the group of Berit Olofsson at Stockholm University, where I advanced my knowledge in both synthesis and computational chemistry, focusing on hypervalent iodine chemistry, as evidenced by my six publications in high-impact journals. During this time, I spent four months as visiting Erasmus PhD student in the group of Daniele Leonori at RWTH University in Germany. During this short period of research, I gained strong expertise in photoredox catalysis and expanded my research beyond iodine chemistry and contribute to a very impressive work published in Nature Catalysis.

– My interest in computational chemistry continued to grow, but I remained dedicated to synthesis. Currently, I am continuing my postdoctoral research in the lab of Professor Keary M. Engle at Scripps Research Institute in USA after receiving the International Postdoc Grant from the Swedish Foundation of International Cooperation in Research and Higher Education. Here, I focus on developing organometallic methods by everaging High-Throughput Experimentation (HTE) and Machine Learning (ML) tools. This position allows me to integrate my interests in both computational and synthetic chemistry, pushing the boundaries of my research further.

Ultimately, my decision to pursue a career in chemistry was driven by the excitement of discovery and the potential to contribute to advancements that can have a significant impact on science and society.

How did you choose to study/work with chemistry?

– I chose to study and work in chemistry because of a deep-seated curiosity about the molecular world and a passion for solving complex problems. From my early academic experiences, I was fascinated by the intricate reactions and processes that drive chemical phenomena. As I progressed through my studies, my interest grew, and I became captivated by both experimental and computational aspects of chemistry. My academic journey has allowed me to explore various fields within chemistry, from synthesis to computational studies, and has provided me with a diverse skill set. Utilizing computational tools alongside laboratory experiments has been particularly rewarding, as it enables the discovery, prediction, and rationalization of novel reactivity. More importantly, this approach not only reduces research costs but also minimizes environmental impact by decreasing the consumption of chemicals. It also accelerates novel discoveries in different fields of research, such as biology, materials science, and medicinal chemistry. Working in different research environments and collaborating with experts across disciplines has enriched my understanding and fueled my passion for chemistry. Ultimately, my decision to pursue a career in chemistry was driven by the excitement of discovery and the potential to contribute to advancements that can have a significant impact on science and society.

The Ludwig Ramberg Dissertation Prize (Ludwig Rambergs avhandlingspris), is handed out every second year by the Division of Organic Chemistry, Kemisamfundet.