Rick Bunt
Office
McCardell Bicentennial Hall 550
Tel
(802) 443-2559
Email
rbunt@middlebury.edu
Office Hours
Spring 2022: Mon 10-12 & Wed 1-2

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.

Courses Taught

Course Description

General Chemistry I
Major topics will include atomic theory and atomic structure; chemical bonding; stoichiometry; introduction to chemical thermodynamics. States of matter; solutions and nuclear chemistry. Laboratory work deals with testing of theories by various quantitative methods. Students with strong secondary school preparation are encouraged to consult the department chair for permission to elect CHEM 0104 or CHEM 0107 in place of this course. CHEM 0103 is also an appropriate course for a student with little or no prior preparation in chemistry who would like to learn about basic chemical principles while fulfilling the SCI or DED distribution requirement. 3 hrs. lect., 3 hrs. lab, 1 hr. disc.

Terms Taught

Fall 2022

Requirements

DED, SCI

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Course Description

Organic Chemistry I: Structure and Reactivity
The lecture portion of this course will be taught using “flipped class” pedagogy. Students will watch videos prior to class, and classroom time will be dedicated to small group problem solving with faculty guidance. The course will provide students with an introduction to the structure and reactivity of organic molecules sufficient to continue directly to the study of biochemistry (CHEM 0322). Topics covered will include models of chemical bonding, acid-base relationships, three-dimensional molecular structure (conformations and stereochemistry), reaction mechanisms and energy diagrams, substitution and elimination reactions, carbonyl reactions (additions, reductions, interconversions, and alpha-reactivity), and the fundamentals of biological molecules (carbohydrates, DNA, and RNA). Laboratory experiments will relate to purification techniques (recrystallization, distillation, extraction, and chromatography), as well as microscale organic reactions that complement the lecture material. (CHEM 0104 or CHEM 0107) 3 hrs. lect., 3 hrs. lab.

Terms Taught

Fall 2018, Spring 2019, Spring 2020, Fall 2021

Requirements

SCI

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Course Description

Organic Chemistry II: Synthesis and Spectroscopy
In this course we will explore how organic molecules are made and their structures are identified. The study of organic reactions will continue from CHEM 0203 with radical reactions, alkene and alkyne additions, aromatic reactions, oxidations and reductions, and additional carbonyl reactions. Emphasis in this course will be placed on using reactions in sequences to synthesize larger and more complex molecules. The theory and practice of mass spectrometry and UV-Vis, IR, and NMR spectroscopy will be studied as a means to elucidate the exact structures of organic molecules. Laboratory experiments will focus on synthetic techniques that complement the lecture material and the identification of complex unknowns via
GC-MS, IR, and NMR. (CHEM 0203) 3 hrs. lect., 3 hrs. lab.

Terms Taught

Fall 2020, Spring 2021

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Course Description

Medicinal Chemistry
Medicinal chemistry combines organic chemistry with biochemistry, analytical chemistry, physical chemistry, molecular biology, pharmacology, and medicine. As chemists we try to correlate the molecular structure of pharmaceutical treatments (i.e., "drugs") with their biological activity to understand disease and to develop both new and improved treatments. In this course we will survey the major categories of diseases, drug targets, and drugs using a case-study approach. In addition to mid-term exams and a shorter group presentation on a disease category, the course will culminate with group-based final projects (presentation and written paper) about the design, development, and proposed future directions of treatments targeting a specific disease. (CHEM 0204 or CHEM 0322) 3 hrs. lect.

Terms Taught

Spring 2022

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Course Description

Instrumental Analysis
In this course we will learn fundamental concepts of analytical chemistry, instrumental analysis, and scientific writing. Lecture topics include experimental design and quality control; sample collection and preparation; calibration, error, and data analysis; statistics; and the theory and operation of chemical instrumentation. Multi-week laboratory projects provide hands-on experience in qualitative and quantitative analysis using a variety of research-quality instrumentation (e.g., UV/Vis spectrophotometry, gas chromatography mass spectrometry, inductively coupled plasma mass spectrometry). Writing workshops promote professional scientific writing skills through guided practice in writing analysis, peer review, and revision. (CHEM 0204 or CHEM 0242) 3 hr. lect., 6 hrs. lab.

Terms Taught

Fall 2018, Fall 2019

Requirements

CW

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Course Description

Independent Study Project
Individual study for qualified students. (Approval required)

Terms Taught

Fall 2018, Winter 2019, Spring 2019, Fall 2019, Winter 2020, Spring 2020, Fall 2020, Winter 2021, Spring 2021, Fall 2021, Winter 2022, Spring 2022, Fall 2022, Winter 2023, Spring 2023

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Course Description

Senior Research
In this course students complete individual projects involving laboratory research on a topic chosen by the student and a faculty advisor. Prior to registering for CHEM 0700, a student must have discussed and agreed upon a project topic with a faculty member in the Chemistry and Biochemistry Department. Attendance at all Chemistry and Biochemistry Department seminars is expected. (Approval required; open only to seniors)

Terms Taught

Fall 2018, Winter 2019, Spring 2019, Fall 2019, Winter 2020, Spring 2020, Fall 2020, Winter 2021, Spring 2021, Fall 2021, Winter 2022, Spring 2022, Fall 2022, Winter 2023, Spring 2023

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Course Description

Senior Thesis
Students who have initiated research projects in CHEM 0400 and who plan to complete a senior thesis should register for CHEM 0701. Students are required to write a thesis, give a public presentation, and defend their thesis before a committee of at least three faculty members. The final grade will be determined by the department. Attendance at all Chemistry and Biochemistry Department seminars is expected. (CHEM 0400; approval required)

Terms Taught

Fall 2018, Winter 2019, Spring 2019, Fall 2019, Winter 2020, Spring 2020, Fall 2020, Winter 2021, Spring 2021, Fall 2021, Winter 2022, Spring 2022, Fall 2022, Winter 2023, Spring 2023

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Course Description

Senior Independent Research
Seniors conducting independent research in Molecular Biology and Biochemistry under the guidance of a faculty mentor should register for MBBC 0700 unless they are completing a thesis project (in which case they should register for MBBC 0701). Additional requirements include attendance at all MBBC-sponsored seminars and seminars sponsored by the faculty mentor’s department, and participation in any scheduled meetings and disciplinary sub-groups and lab groups. (Approval required).

Terms Taught

Fall 2018, Fall 2019, Fall 2020, Winter 2021, Fall 2021, Winter 2022, Fall 2022, Winter 2023

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Course Description

Senior Thesis
This course is for seniors completing independent thesis research in Molecular Biology and Biochemistry that was initiated in BIOL 0500, CHEM 0400, MBBC 0500, or MBBC 0700. Students will attend weekly meetings with their designated research group and engage in one-on-one meetings with their research mentor to foster understanding in their specialized research area. Students will also practice the stylistic and technical aspects of scientific writing needed to write their thesis. (BIOL 0500, CHEM 0400, MBBC 0500, MBBC 0700) (Approval required).

Terms Taught

Fall 2021, Fall 2022

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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.