This project will continue work on the development of catalytic, exo selective and enantioselective Diels-Alder reactions. Boron and silicon-substituted dienes, which offer practical advantages over transition metal-substituted dienes in terms of cost and disposal, will be prepared and utilized in catalytic chemistry and tandem reactions. These dienes can be used to reverse the normal endo selectivity of Diels-Alder reactions and provide access to new cycloadduct stereoisomers in high yield, diastereoselectivity and enantioselectivity. This synthetic method will provide access to relative and absolute cycloadduct stereochemistries that were not readily available previously through endo-selective Diels-Alder reactions of the polymerization-prone Z-dienes.
With this award, the Organic and Macromolecular Chemistry Program is supporting the research of Professor Mark Welker of the Department of Chemistry at Wake Forest University. Professor Welker's research efforts revolve around the development of tandem Diels-Alder/hydrolysis and Diels-Alder/cross coupling reactions. The products of these tandem reactions have biological activities ranging from insect anti-feedants to biomedical science applications. The successful development of the methodology therefore will have an impact on synthesis in the pharmaceutical and agricultural industries.
Intelleculat Merit. This new chemical reactions developed with this award provide access to core structures in the cis clerodane terpenes which have biological activities ranging from insect antifeedants to biomedical applications. Most recently, we prepared boron and silicon-substituted dienes, which offer practical advantages over transition metal-substituted dienes in terms of preparation, cost and disposal and are more amenable to catalytic chemistry and tandem reactions. Broader Impacts: Contributions to the Development of Organic Chemistry and Human Resources. Our previous work in metal diene chemistry has been cited almost five hundred times as of 2013 (2 papers on this topic with >55 citations each and two others > 35 citations each). Since the summer of 2007, the PI supervised 9 graduate students (5 completed PhDs and 2 completed MS degrees; 2 continuing PhD students) and 15 undergraduate research students. Three of the 15 PhD recipients from this group have won national postdoctoral fellowships: 1 NIH NRSA, 1 Merck/UNCF, and 1 American Heart Association. Students who work on this project are broadly trained in synthetic organic and organometallic chemistry, and most have secured careers in the pharmaceutical or specialty chemicals industries or in academic positions. Students from the Welker group routinely do science presentations at elementary schools in the Winston-Salem/Forsyth County schools and offer lab tours to visiting groups of middle and high school students. Two former Welker group trainees are now Chemistry faculty (Franks and Pinder) at HBCU NC A & T State University in Greensboro, NC and two PhD trainees in the previous funding period have been African-American women. The PI has worked on state science policy formation as a member of the NC Board of Science and Technology for the last 10 years. During the previous funding period, the PI contributed an op/ed to the Triad Business Journal on science and business and was elected as a Fellow by the American Association for the Advancement of Science for "contributions to the field of organometallic chemistry, particularly for metal-mediated cyclization and cycloaddition reactions." Two of the silicon substituted dienes which we prepared with NSF support are offered commercially now by Strem Chemicals, Inc.: www.strem.com/catalog/v/14-1960/63/silicon_1026785-83-0 and www.strem.com/catalog/v/14-1965/63/silicon_1021940-25-9.
