This project will continue work on the development of new synthetic methodologies based on the chemistry of hypervalent iodine(III) and iodine(V) compounds, which are efficient and environmentally benign oxidizing reagents with numerous applications in organic synthesis. While hypervalent iodine compounds are well-established reagents, little progress has been made in the development of new catalytic reactions promoted by hypervalent iodine. Studies of new, extremely mild and efficient iodine(V)/transition metal tandem catalytic system for the oxidation of hydrocarbons will be investigated using various aryliodides and transition metals as co-catalysts and Oxone as a stoichiometric oxidant. Several other iodoarene-catalyzed oxidative transformations, such as Hofmann rearrangement of amides to amines, preparation of unsaturated carbonyl compounds from ketones, oxidative cleavage of carbon-carbon double bonds, and the iodine(III)-catalyzed enantioselective oxidations will also be studied. An exploratory search for new and potentially useful hypervalent organic compounds will be also performed. In addition, an important objective of this project is to provide excellent training in advanced chemistry research to BS and MS students and to further strengthen predominantly undergraduate research at University of Minnesota Duluth.
With this award, the Chemical Synthesis program is supporting the research of Professor Viktor V. Zhdankin of the Department of Chemistry and Biochemistry at University of Minnesota Duluth. Professor Zhdankin's research efforts revolve around the development of facile oxidative methods based on hypervalent iodine chemistry. Such chemistry will contribute to environmentally benign methods for chemical synthesis as it utilizes non-toxic compounds of iodine as catalysts or recyclable reagents in aqueous solutions. Successful development of the methodology will have an impact on synthesis in the pharmaceutical industry.
This NSF-supported research project has been aimed at the exploration of the chemistry of polyvalent iodine compounds, which are efficient and environmentally benign oxidizing reagents with numerous applications in organic synthesis. Organic compounds of polyvalent iodine, which are also known under the general name of hypervalent iodine reagents, have chemical properties similar to the derivatives of transition metals, but without the toxicity and environmental problems of these heavy metal congeners. While hypervalent iodine compounds are well-established stoichiometric reagents, little progress has previously been made in the development of catalytic reactions promoted by hypervalent iodine. In the course of this project, several new reactions catalyzed by hypervalent iodine have been discovered. For example, a metal-free catalytic procedure for aziridination of alkenes using organic iodide as a catalyst has been developed. This reaction allows efficient and environmentally safe access to aziridines, which are widely used as building blocks in synthetic organic chemistry and pharmaceutical industry. During this project, significant research efforts have been dedicated to the development of 'green' synthetic methodologies based of the recyclable hypervalent iodine reagents. In particular, a series of new polymer-supported hypervalent iodine reagents, such as, polystyrene-supported iodine(III) sulfate, polystyrene-supported (dichloroiodo)benzene, and polystyrene-supported iodosylbenzene have been prepared and evaluated. These new products are potentially important as recyclable, environmentally friendly reagents and catalysts that have wide applicability to organic synthesis including the solid-phase and combinatorial high throughput synthesis techniques. Several new nonpolymeric recyclable hypervalent iodine reagents have also been developed. These reagents (for example, 2-iodylpyridines) have some advantages over the polymer-supported reagents, such as, better solubility and greater stability toward oxidation. In addition, synthetic and structural studies of several new classes of hypervalent iodine compounds have been performed. Specifically, a series of heterocyclic compounds containing trivalent iodine, oxygen, and boron in a five-membered ring (benziodoxaboroles) were prepared and structurally investigated by X-ray crystallography. All these new recyclable iodine reagents are potentially important for the development of green industrial technologies. The results of this project were published in 25 papers (including three reviews and the J. Org. Chem. Perspective, which has been #2 on the 2011 list of the J. Org. Chem. "Most Read Articles"), reported as 8 presentations at national meetings of American Chemical Society (including an Award Address at the national award symposium at the ACS meeting in 2011), presented as 3 invited lectures and 3 short courses at several international conferences. This research has contributed to the field of chemistry through discovery of new classes of hypervalent iodine compounds and development of synthetic methodologies based on these compounds. New synthetic methodology based on iodine chemistry is a valuable contribution to environmentally benign methods for chemical synthesis as it utilizes non-toxic compounds of iodine as catalysts or recyclable reagents in aqueous solutions. Successful development of this methodology will have an impact on any area of activity in which the synthesis of molecules is needed, such as the pharmaceutical, chemical, agricultural industry, and the biological and chemical research activities. In addition, this project provided excellent training to 5 undergraduates, 6 M.S. students, and one postdoctoral fellow. All these students have received an excellent research experience and training in synthetic organic chemistry, coauthored scientific papers, and gave numerous scientific presentations on their research.