Tags: Organic Seminar


Enzymatic Catalyzation of Diazo Compounds for the Formation of Lactones: An Intramolecular C–H Functionalization Strategy

Diazo compounds were first discovered by Peter Griess in 1858.1 The diazo group has been widely used due to its diverse reactivity, including alkylation, carbene generation, nucleophilic addition, homologation, and ring expansion.  These compounds can react with a wide number of transition metal complexes capable of transferring carbenes, including carbene insertion reactions into C–H, Si–H, N–H, O–H, and S–H bonds, sulfur ylide mediated…


Total Synthesis of Gelsemium Alkaloids and Synthesis of Ketohydroperoxides

    The Gelsemium alkaloids were first isolated from Gelsemium elegans and sempervirens in the 1870s. Despite their acute toxicity, they were documented for their potent analgesic properties and were first used in traditional Asian medicine. Our group achieved the first total synthesis of gelsenicine in 2016 using an Au(I)-catalyzed cycloisomerization/Cope rearrangement to forge the oxabicyclo[3.2.2]nonane skeletal…


Synthesis of Erythropoietin

Since approval by the FDA in 1989, erythropoietin (EPO) has been used extensively for the treatment of anemia – especially in those with chronic kidney disease, undergoing chemotherapy, or have acquired immune deficiency syndrome (AIDS).1 EPO is a highly glycosylated glycoprotein containing three N-linked and one O-linked glycosylation sites. These glycans constitute 40% of the weight of the glycoprotein and are important for activity.2 It has…


Synthesis and Application of Functional Nanoparticles for Precision Drug Delivery

Nanoparticles (NPs) are particles of approximately 1-100 nm in size and have properties not found in bulk samples of the same material. Different materials, such as polymers, metal oxides, silica, noble metals, and carbon, can be used to create nanoparticles, which can then carry a variety of bioactive substances for use in biomedical applications, such as proteins, nucleic acids, small molecules for chemotherapy, and diagnostics. Owing to their…


Mechanistic Underpinnings of Phototoxicity and Photobluing: Using Organic Photochemistry and DFT to Help Solve Problems in Photomedicine and Photobiology

My research group is interested in mechanistic insights to sort out the reactive oxygen intermediates in photooxidation reactions. We have made contributions to the fields of photooxidation and oxygen-transfer processes, including singlet-oxygen disinfection priming and selective oxidations. In this seminar, one topic to be discussed is the shrinking of a molecular gap (so-to-speak), that is improving of mechanistic understanding of a…


Recent Advances of Metal Carbenoids: from Diazo Precursors to Safe Carbene Precursor

Fischer carbene complexes with six valence electrons, characterized by a singlet carbene center, demonstrate an amphiphilic nature.1 The transition metal carbene complexes share similarities with Fischer carbene complexes, potentially functioning as both nucleophiles and electrophiles.2 This duality enables chemists to accomplish intricate transformations, such as C-H bond insertion or cyclopropanation. Despite their utility, the synthetic…


Sulfur (VI) Fluoride Exchange (SuFEx) in Drug Discovery

The concept of click chemistry was first introduced by Sharpless and his coworkers in 20011 , with the copper-mediated azide-alkyne cycloaddition (CuAAC) being the first click reaction to be introduced. Although a robust and precise reaction, ligating azides with terminal alkynes to afford 1,4-disubstituted triazoles, CuAAC was inherently limited due to its utilization of toxic copper metal as well as its limiting requirement for pre-…


Guest Speaker: Prof. Jón Njardarson


Improvement of α-amino Ester Hydrolase (AEH) Via Rational Design, Computational Design, and Machine Learning (ML)

Current batch enzymatic processes to important semi-synthetic beta-lactam antibiotics, such as amoxicillin and cephalexin, suffer from yield and selectivity limitations, owing to primary and secondary hydrolysis side reactions (see Figure). Through continuous flow and reactive crystallization of the beta-lactam product, we sought to suppress primary hydrolysis and prevent secondary hydrolysis. Indeed, we found higher yields than in homogenous…


Guest Speaker: Prof. Liming Zhang

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