COVID-19: Essential Information

Rick Bunt

Assoc. Dean of the Sciences; Joseph Burr Prof of Chem/Biochem

 
 work(802) 443-2559
 Fall 2020 on Zoom: Mon 12:30-2:00PM, Wed 1:00-2:30, and by appointment
 McCardell Bicen Hall 550

Our research is motivated by a desire to understand how catalytic process occur at the detailed molecular level. In particular, we study palladium-catalyzed allylic-addition reactions and explore the functioning of chiral ligands. We are most interested in how three-dimensional “chiral information” is transmitted from the ligand, across the metal, to the reacting centers. We employ a combination of organic synthesis, physical organic methods, and one and two dimensional NMR spectroscopy, to study these reactions.

A series of chiral phosphinooxazoline (PHOX) ligands containing electron donating and withdrawing groups on the aryl backbone have been synthesized. The effects of these electronic perturbations are determined by measuring the enantiomeric excess of the alkylation and amination reaction products by chiral HPLC and by measuring the changes in the 13C NMR chemical shifts of the isolated p-allylpalladium intermediate complexes on the department's 400 MHz NMR spectrometer. The observed effects are then mathematically correlated to the electronic perturbations via Hammett and other types of linear free-energy relationship (LFER) analyses of the data.

 

Recent Awards

2007 Perkins Award for Excellence in Teaching

Recent Publications

Bryan S. Holtzman,# Eric T. Roberts,# Nicholas S. Caminiti,# Jacob A. Fox,# Madison B. Goodstein,# Staci A. Hill,# Zitong B. Jia,# Isabelle N. –M. Leibler,# Michael L. Martini,# Gina M. Mendolia,# Molly S. Costanza-Robinson, and Richard C. Bunt, Ligand and base additive effects on the reversibility of nucleophilic addition in palladium-catalyzed allylic aminations monitored by nucleophile crossover. Tetrahedron Lett. 2017, 58, 432.

*Nicholas S. Caminiti,*Madison B. Goodstein, *Isabelle N.-M . Leibler,*Bryan S. Holtzman, *Zitong B. Jia,  *Michael L. Martini, *Nathaniel C. Nelson,and Richard C. Bunt, Reversible nucleophilic addition can lower the observed enantioselectivity in palladium-catalyzed allylic amination reactions with a variety of chiral ligands. Tetrahedron Lett. 2015, 56, 5445.

Richard C. Bunt, Charlotte Majerczyk, Mitchell Brittnacher, Michael Jacobs, Christopher Armour, Matthew Radey, Hillary Hayden, Ryland Bydalek, and E. Peter Greenberg, “A cross-species comparison of the Burkholderia pseudomallei, Burkholderia thailandensis, and Burkholderia mallei quorum sensing regulons,” Journal of Bacteriology 2014, 196, 22, 3862.

Richard C. Bunt, Charlotte Majerczyk, Mitchell Brittnacher, Michael Jacobs, Christopher D. Armour, Mathew Radey, Emily Schneider, Somsak Phattarasokul, and E. Peter Greenberg, “Global Analysis of the Burkholderia thailandensis Quorum Sensing-Controlled Regulon,” Journal of Bacteriology, 2014, 196, 7, 1421.

Charlotte Majerczyk, Mitchell Brittnacher, Michael Jacobs, Christopher D. Armour, Mathew Radey, Emily Schneider, Somsak Phattarasokul, Richard Bunt and E. Peter Greenberg “Global Analysis of the Burkholderia thailandensis Quorum Sensing-Controlled Regulon” J. Bacteriol. 2014, 196, 7, 1412.

Charlotte Majerczyk, Loren Kinman, Tony Han, Richard Bunt, and E. Peter Greenberg “Virulence of Burkholderia mallei Quorum-Sensing Mutants” Infect. Immun. 2013, 81, 5, 1471.

*Armstrong, P.B., *Dembicer, E.A., *Desbois, A.J., *Fitzgerald, J.T., *Gehrmann, J.K., *Nelson, N.C., *Noble, A.L., Bunt, R.C. “Investigation of the Electronic Origin of Asymmetric Induction in Palladium-Catalyzed Allylic Substitutions with Phosphinooxazoline (PHOX) Ligands by Hammett and
Swain–Lupton Analysis of the 13C NMR Chemical Shifts of the (π-Allyl)palladium Intermediates.” Organometallics 2012, 31, 6933-6946. DOI: 10.1021/om3007163

Paul B. Armstrong,# Lisa M. Bennett, Ryan N. Constantine,# Jessica L. Fields,# Jerry P. Jasinski, Richard J. Staples, Richard C. Bunt "Hammett 13C NMR and X-ray studies of allylpalladium phosphinooxazoline chiral ligand complexes", Tetrahedron Lett. 2005, 46, 1441-1445.

Sunhee Choi, Richard B. Cooley,# Amanda S. Hakemian, # Yuna C. Larrabee, Richard C. Bunt, Stéphane D. Maupas, James G. Muller, and Cynthia J. Burrows, "Mechanism of Two-Electron Oxidation of Deoxyguanosine 5'-Monophosphate by a Platinum(IV) Complex" J. Am. Chem. Soc. 2004, 126, 591.

Ryan N. Constantine,# Naomi Kim,# and Richard C. Bunt, "Hammett Studies of Enantiocontrol by PHOX Ligands in Pd-Catalyzed Allylic Substitution Reactions" Org. Lett. 2003, 5, 2279.

Grants

2007 American Chemical Society-Petroleum Research Fund, "Hammett Studies of P,N-Chiral Ligands." 9/1/07- 8/31/10 ($55,000)

2007 National Science Foundation (NSF-RUI, CHE-0714541) "Hammett Studies of P,N-Chiral Ligands.", 8/15/07- 8/14/10 ($146,000)

2005 Vermont Genetics Network (NIH-BRIN), Equipment Grant for "A Solvent Purification System" Co-PI with Jeff Byers ($24,700)

2003 National Institutes of Health (NIH-AREA), "Mechanism of Base-Flipping by DNA Modifying Enzymes" ($137,971)

2003 Pfizer Summer Undergraduate Research Fellowship for Sarah S. Goodwin ($5,000)

2002 Vermont Genetics Network (NIH-BRIN), Partial Sabbatical Leave Support for "Altering the Rate of Base Flipping in DNA" ($20,000) 

2001 American Chemical Society-Petroleum Research Fund, Type G, "Probing the Electronic Origins of Chiral Ligand Asymmetry in Palladium-Catalyzed Allylic-Alkylation Reactions" ($25,000)

2001 Cottrell College Science Award from Research Corporation, "Probing the electronic origins of chiral ligand asymmetry in palladium-catalyzed allylic-aklylation reactions" ($41,381)

2000 Pfizer Summer Undergraduate Research Fellowship for Agnes Makingwe ($5,000)

2000 VT EPSCoR Award, "Electronic Control of Chiral Ligand Asymmetry" ($5,500)

 

Department of Chemistry & Biochemistry

McCardell Bicentennial Hall
276 Bicentennial Way
Middlebury College
Middlebury, VT 05753