Boston College Graduate Student Symposium

October 9, 2017 8:00 am – 6:00 pm

Connors Family Retreat and Conference Center Dover, MA

Dear Friends and Colleagues,

Welcome to the 2017 Boston College Chemistry Department Graduate Student Symposium! This annual symposium allows graduate students in the department to share their research accomplishments with fellow students and faculty. We have an impressive lineup of speakers and poster presenters and we hope that you enjoy this opportunity to learn about the diverse areas of research currently ongoing in the Chemistry Department.

In addition, it is our pleasure to welcome alumnus Dr.

Jamie Garcia, research staff member at IBM. She is a graduate of the Hoveyda lab. We are very grateful to Dr. Garcia for her participation in this event and for giving us insight into her successful career path so she can serve as an exceptional role model for current graduate students.

Please enjoy your day at the beautiful Connors Family

Retreat and Conference Center!

Sincerely,

Paul Hicks, Vincent Ovalle, Katherine Grasso, Matthew Thompson (Chemistry GSA Representatives) Professor Jia Niu

Connors Family Retreat and Conference Center

20 Glen Street

Dover, MA

Schedule of Events: ***Buses depart from Merkert Chemistry Center at 7:15am*** 8:00 am – 8:45 am

Breakfast

8:45 am – 9:10 am

Student Presentation 1 – James Italia

9:10 am – 9:35 am

Student Presentation 2 – Farid Van Der Mei

9:35 am – 10:00 am

Student Presentation 3 – Qi Dong

10:00 am – 10:15 am

Break – Coffee Break

10:15 am – 10:40 am

Student Presentation 4 – Katherine Boknevitz

10:40 am – 11:05 am Student Presentation 5 – Charuni Gunathunge

11:05 am – 12:00 pm

Student Poster Session 1 – Shaochen Zhang, Xavier Riart-Ferrer, Kayla Delle Chiaie, Xiang Li, Yang Li, Wenjian Wang, Diana Fager, Jingru Luo, Chenlong Zhang, Aaron Maurais

12:00 pm – 1:00 pm

Lunch

1:00 pm – 1:25 pm

Student Presentation 6 – Yejin Chang

1:25 pm – 1:50 pm

Student Presentation 7 – Sam Cambray

1:50 pm – 2:15 pm 2:15 pm – 2:30 pm

Student Presentation 8 – Xin Wen Break – Cookie Break

2:30 pm – 3:50 pm Student Poster Session 2 – Yuanzhe Zhang, Ben Williams, Miao Qi, Jingyi Wang, Sarah Erickson, Min Cao, Ryan Morrison, Michael Crockett, Jesse Myhill, Qifan Wang, Yanyan Zhao, Yuebiao Zhou, Yong Wang, Cameron McConnell, Kyle Cole

4:00 pm – 5:00 pm Keynote Speaker – Jamie Garcia, PhD

5:00 pm – 5:25 pm Student Presentation 9 – Zhehui Li

5:25 pm – 5:50 pm Student Presentation 10 – Gabriel Lovinger ***Buses depart for Boston College around 6:00 pm***

Poster Session Titles

Greystone Meeting Room 11:05 am - 12:00 pm 2:30 pm – 3:50 pm

Physical and Theoretical Chemistry Tsung Group "Synthesis of Shaped Intermetallic Nanoframes through the Low-Temperature Annealing of Core-Sandwich-Shell Nanoparticles" -Benjamin Williams "From Zeolitic Imidazolate Frameworks to Robust Zirconium based Metal-Organic frameworks: NP@UiO, Core-shell and Hollow UiOs." -Yang Li Waegele Group “Reversible Surface Reconstruction of Copper Electrodes Spectroscopically Monitored under Conditions of Carbon Dioxide Reduction” -Xiang Li Wang Group "Stable Iridium Dual Atom Catalyst Supported on Metal Oxide Substrate" -Yanyan Zhao "Post Lithium-ion batteries: From lithium to magnesium" -Jingru Luo

Chemical Biology and Biochemistry Chatterjee Group Using site specific chemistry to understand and manipulate Adeno-Associated Virus -Sarah Erickson Gao Group "A Foldable Prolinomycin-based Scaffold: From Structure to Function” -Wenjian Wang

Weerapana Group "Synthesis and Characterization of Triazine-Based Covalent Inhibitors of Protein Disulfide Isomerase A1" - Kyle Cole “Proteomic Strategies to Study Post-Translational Modifications” - Aaron Maurais

Organic and Organometallic Chemistry Byers Group “Iron-Catalyzed Suzkuki-Miyaura Cross-Coupling Reactions Between Alkyl Halides and Unactivated Aryl Boronic Esters”

-Michael Crockett “Exploration of versatile bis(imino)pyridine iron alkoxide catalysts for ring-opening polymerization” -Kayla Delle Chiaie “E-switchable Polymerization”

-Miao Qi Hoveyda Group “Catalytic Enantioselective Addition of Organoboron Reagents to α-Halogenated Ketones: Access to 1,1-Disubstituted Epoxides and α-Haloaldehydes” -Diana Fager "NHC-Cu-Catalyzed SN2’’- and Enantioselective Allylic Substitution with an Allenylboronate" -Yuebiao Zhao “An Efficient and Practical Method for Diastereo- and Enantioselective Synthesis of Vicinal Aminoalcohols”

-Ryan Morrison "Expedient Synthesis of Highly Functionalized Primary Amines from Nitriles through a Copper-catalyzed Four-component Reaction"

-Shaochen Zhang

Liu Group "Azaborine-Based Ligand Platforms for Metal-Catalyzed Reactions" -Yuanzhe Zhang "Differential Reactivity of Borylated-Azaborine Regioisomers: Applications in the Synthesis of BN-Styrenes"

-Cameron McConnell Morken Group "Enantioselective Synthesis of Organoboronates by Catalytic Conjunctive Cross Coupling" -Jessie Myhill "Catalytic Synthesis of Nonracemic Geminal Silylboronates" -Chenlong Zhang Wasa Group “Enantioselective Cooperative Catalysis Using Frustrated Acid/Base Complexes” -Min Cao "Stereoselective synthesis of chiral amines through lewis acid-catalyzed hydride abstraction"

-Qifan Wang

Zhang Group “Intermolecular Olefin Aziridination via Stereoselective Metalloradical Catalysis” -Xavier Riart-Ferrer "Asymmetric Radical Reactions with In Situ-Generated Diazo Compounds as Radical Precursors via Co(II)-Based MRC" -Yong Wang “Highly Enantioselective Intramolecular Radical Cyclopropanation: New Application of Co(II)-Based Metalloradical Catalysis to Construct Chiral Benzo(3-oxabicyclo[4.1.0]heptan-2-one) Structures” -Jingyi Wang

Keynote Speaker

Charles River Meeting Room 4:00 pm – 5:00 pm

Jamie M. Garcia, PhD IBM T.J. Watson Research Center

Yorktown Heights, NY Education: Ph.D. – Boston College, 2006-2012 (Advisor: Dr. Amir H. Hoveyda) B.S. – Seattle University, 2001-2006 Experience: Research Staff Member and Technical Assistant to Sophie Vandebroek, PhD- Sep 2017-present, IBM Research Staff Member – July 2012-present IBM

Engineering Polymers from Secondhand Materials

Of the ~34 million tons of plastic annually in the US, less than 10% of it is recycled. Although this may be due to consumer cooperation and/or cultural leanings within the US, technological challenges remain as a principal limiting factor for plastics recycling. In this talk, I will present our recent work on new recyclable networks and discuss new approaches to the chemical depolymerization of commercial polymers.

Lecture Abstracts

Charles River Meeting Room

8:45 am – 10:00 am 10:15 am – 11:05 am

1:00 pm – 2:15 pm 5:00 pm – 5:50 pm

Development and Applications of Universal Genetic Code Expansion

Platforms

James Italia and Abhishek Chatterjee

The ability to site specifically incorporate unnatural amino acids (UAAs) into proteins in living cells has emerged as a powerful method to probe and manipulate protein structure and function. At the core of this technology is an engineered aminoacyl-tRNA synthetase (aaRS)/tRNA pair that inserts an UAA in response to a repurposed nonsense codon during translation. To ensure that this UAA-specific pair does not cross-react with its endogenous counterparts (i.e., orthogonal), it must be imported into the host cell from a different domain of life. Thus, UAA-incorporation in bacteria relies on eukaryote/archaea derived aaRS/tRNA pairs, while the same in eukaryotes uses bacteria-derived pairs. Consequently, for each desired UAA, two distinct incorporation system must be developed, which represents a significant limitation.

We have developed a general approach to overcome this limitation by functionally replacing an aaRS/tRNA pair of E. coli with its eukaryotic/archaeal counterpart. The “liberated” pair can be then reintroduced into the resulting E. coli strain as an orthogonal nonsense suppressor, engineered to selectively charge UAAs of interest, and used to site-specifically incorporate UAAs into proteins expressed in both the engineered E. coli strain and any eukaryote (e.g., human cells). The ability to engineer such bacteria-derived “universally orthogonal” pairs using the facile E. coli based platform also makes it significantly easier to genetically encode new UAAs in eukaryotes – a process which previously relied on a cumbersome yeast-based platform. Over the last three years, we have demonstrated the feasibility of this strategy by developing two such universal aaRS/tRNA pairs for UAA incorporation: tyrosyl and tryptophanyl. We have also engineered these to genetically encode many useful UAAs, including those enabling bio-orthogonal protein labeling and modeling of important protein post-translational modifications. These new aaRS/tRNA pairs can also be used together to site-specifically incorporate multiple distinct UAAs into proteins with high fidelity and efficiency, unlocking powerful new applications.

Efficient, Regio-, Z-, and Enantioselective Additions of Substituted

Allyl Borons to Aldehydes

Farid Van Der Mei and Amir H. Hoveyda

Catalytic enantioselective allylation reactions of aldehydes is a synthetically important transformation which produces complex compounds with handles for further functionalization. Previous attempts utilizing the aminophenol pre-catalyst in these reactions have resulted in products with low levels of enantioselectivity. However, new insights into the transformation have shown that by employing substituted Z-allyl boron reagents, high levels of Z- and enantioselectivity can be obtained. The reaction scope is being developed for Z-CF3 and Z-Cl substituted allyl B(pin) reagents and the utility will be highlighted by a short total synthesis.

Towards Stable Li-O2 Batteries and Beyond

Qi Dong and Dunwei Wang

As the most promising post-Li- ion technology, Li-O2 battery features high gravimetric energy density. Even by the more conservative estimate, Li-O2 batteries are of much higher specific energy (>2,000 Wh/kg) than the state-of- the-art Li-ion batteries (~400 Wh/kg). However, the development of Li-O2 battery into a practical technology hinges on the availability of a stable electrolyte. Due to the high reactivity of oxygen species in the system, no known organic electrolytes meet the stability requirements, and the search for a stable electrolyte system remains an outstanding challenge in Li-O2 battery research.

In this presentation, we show that the issue can be solved by using a new water-in- salt electrolyte system that involves no organic solvents. In essence, the electrolyte consists of super-concentrated LiTFSI (21 molality of lithium bis(trifluoromethanesulfonyl)imide), in which H2O molecules are locked to the ions and do not exhibit reactivity toward Li2O2 or other oxygen species. The net result is a highly effective electrolyte that enables stable Li-O2 battery operations for at least 300 cycles with no measurable parasitic chemical reactions. A new door to practical Li-O2 batteries with high performance is opened up.

Synthesis, Characterization, and Application of an Unnatural Boron

and Nitrogen Containing Isostere of Tryptophan

Katherine Boknevitz and Shih-Yuan Liu*

Boron and nitrogen (BN) containing heterocycles, such as 1,2-azaborines, have an isosteric and isoelectronic relationship with their carbonaceous counterparts, marking them as ideal targets for biological and medicinal studies. Tryptophan, which is an essential amino acid, has been studied due to its importance in protein structure and function, as well as its role as the main source of intrinsic protein fluorescence. Incorporation of a BN bond into tryptophan through a late stage functionalization of the BN-indole offers a new analogue of this amino acid. This presentation will discuss the synthesis of BN-tryptophan, its properties in comparison with natural tryptophan, and its application as an unnatural amino acid.

NH

BN

NH

NH2

OHO

NH2

OHO

Isoelectronic

Isostructural

NaturalTryptophan BN-Tryptophan

Probing Promoting Effects of Alkali Cations on the Reduction of CO

at the Aqueous Electrolyte/Copper Interface

Charuni Gunathunge, Vincent Ovalle and Matthias Waegele

The catalytic selectivity and reactivity of an electrocatalytic interface can profoundly depend on the identity of the supporting electrolyte’s cation. In the case of CO2 reduction on copper electrodes, these cation effects have been utilized to suppress undesired hydrogen evolution and to promote the formation of C2 reduction products. However, to more effectively steer the catalytic selectivity of the electrolyte/copper interface by cations, it is crucial to reveal the various physical mechanisms by which cations impact the catalytic properties of this prototypical interface for CO2 reduction. Herein, we employ surface-sensitive infrared spectroscopy to probe how alkali cations (Li+ , K+ , and Cs+ ) control the coverage of CO, a key intermediate in CO2 reduction, on a polycrystalline copper electrode. We find that surface-adsorbed CO experiences an increasingly larger electrostatic stabilization with increasing cation size. The reduction of CO is further promoted by the two larger cations, leading to a significant drop of the CO coverage at high cathodic potential around -1 V vs. RHE. Our results demonstrate for the first time that the coverage of CO on the electrode is very sensitive to the identity of the cation. Since the relative coverage of CO and hydrogen on the copper surface affects the catalytic rates of CO2 reduction and hydrogen evolution, our results represent an essential step towards a better understanding of how cation effects control the product distribution.

1

0

Nor

m. B

and

Are

a

1

0

-1.4 -1.2 -1.0 -0.8 -0.6 -0.4 Potential (V) vs. SHE

Li+

Cs+

- - - - -

Cs+

δ-

δ+

E-Field

CO

Enantioselective C-C Bond Forming Reactions Through Lewis Acid-Catalyzed Hydride Abstraction of Amines

Yejin Chang and Masayuki Wasa

Chiral α-substituted amines are important synthetic targets since they are

prevalent in pharmaceuticals as well as chiral catalysts that are used in enantioselective synthesis. Transformations involving α-amino C-H bonds in N-alkylamines and promoted by transition metal complexes have therefore received considerable attention. However, the state-of-the-art in stereoselective transformations of α-amino C-H bonds remains limited in scope and practicality. Herein, we describe an efficient preparation of chiral α-substituted amines, which proceeds through Lewis acid-catalyzed hydride abstraction of amines. The use of a sterically encumbered organoborane and hindered N-alkylamine circumvents the formation of a “classic” acid/base adduct. Instead, the Lewis acid catalyst promotes the formation of an iminium ion intermediate from amine 1a, which is then attacked by various carbon nucleophiles to afford α-substituted amines (e.g., 3a, 3b). Enantioselective Mannich reaction between amine 1a and Michael acceptor 2b was achieved through the development of cooperative acid/acid catalysts.

NAr

O

XNAr

H X

OTMSR1

R2 R1 R2

NAr

H B(C6F5)3

B(C6F5)3cat.

3a(rac)

1a 2a

+

X

OR1

R2

TMS

HTMSB(C6F5)3

NAr

H X

OR1

B(C6F5)3cat.

1a 2b

+

R2Mg(OTf)2cat.

L*cat.

NAr

3bup to 98:2 er

O

XR1 R2

H

**

NAr

H B(C6F5)3

X

OR1

R2 NAr

X

OR1

R2B(C6F5)3

ML*

H

B(C6F5)3

B(C6F5)3 ML*

NON N

O

ArAr

Lewis Acid-Catalyzed Mannich Reaction Enantioselective Mannich Reaction Catalyzed by Cooperative Acid/Acid Complexes

ML*

Versatile Conjugation Chemistries of ortho-Boronic Acid Substituted Aryl Ketones and Aldehydes for Diverse Biological Applications

Sam Cambray and Jianmin Gao

The field of bioorthogonal chemistry has experienced a significant

expansion in the last two decades due to advances in our understanding of the underlying principles that govern biocompatibility. The advent of these chemistries has allowed for targeted facile labeling and detection of important biomolecules; however, identification of highly biocompatible conjugation chemistries has been a challenge, as chemistry that is fast, stable and non-toxic in neutral, aqueous conditions remains a rare commodity. However, the innovation of ortho-boronic accelerated reactions of aryl ketones and aldehydes has opened up a new area of biocompatible chemistries that affords facile, biocompatible conjugation to a wide variety of reactive partners, including simple amines, oximes and hydrazines, with a dynamic range of stabilities. This in turn has afforded both targeted identification and labeling of important biomolecules, such as proteins and membrane lipids, as well as ligation reactions that can be carried out in biological systems with biochemically installed moieties. Thus, the discovery of boronic acid accelerated conjugation reactions has greatly expanded the toolbox of bioorthogonal conjugation and overcome many of the challenges presented by biocompatibility.

OH/H3CB(OH)2

H2N

HSOH

O

B(OH)2NHS OHO

H/H3C

H2NHN RH2N

R

H2NO R

NH/H3CBN R

OH

NH/H3CB(OH)2

R

NH/H3CB(OH)2

O R

Asymmetric Radical C–H Alkylation via Co(II)-Based Metalloradical Catalysis: Synthesis of Optically Active 2-Substituted Indolines

Xin Wen and X. Peter Zhang

Complementary to the conventional C–H alkylation through heterolytic

bond cleavage, homolytic C–H alkylation processes have attracted a surge of interest and become increasingly important since radical activation of inert C(sp3)–H bonds allows for the rapid construction of C−C bonds. As effective metalloradical catalysts, open-shell Co(II) complexes of D2-symmetric chiral amidoporphyrins [Co(D2-Por*)] have been vastly developed to formulate fundamentally new types of α-Co(III)-alkyl radicals (also known as Co(III)-carbene radicals) via the activation of various radical precursors. These confined C-centered radicals have been applied as key intermediates in a wide array of asymmetric radical transformations. In this work, we have demonstrated an enantioselective radical C–H alkylation approach for the rapid access of optically active substituted indoline derivatives. Through the design and synthesis of a new D2-symmetric chiral amidoporphyrin as the supporting ligand, the Co(II)-based metalloradical system enables efficient activation of in-situ generated aryldiazomethanes as radical precursors for enantioselective radical alkylation of a broad range of C(sp3)–H bonds, including benzylic, propargylic as well as aliphatic C–H bonds, delivering the corresponding indoline derivatives in high yields with excellent enantioselectivities. The newly developed method would enable novel bond disconnections as well as expand the repertoire of these biologically relevant compounds synthesis.

Aperture-Opening Encapsulation of a Transition Metal Catalyst in a Metal-Organic Framework for CO2 Hydrogenation

Zhehui Li and Jeffrey Byers

Aperture-opening resulting from dissociative linker exchange in the robust

zirconium-based metal-organic framework (MOF) UiO-66 was employed to encapsulate the homogeneous ruthenium complex (tBuPNP)Ru(CO)HCl (tBuPNP = 2,6-bis((di-tert-butyl-phosphino)methyl)pyridine) in the framework. The resulting encapsulated complex, [Ru]@UiO-66, was an active catalyst for the hydrogenation of carbon dioxide under mild conditions. Unlike the homogeneous catalyst, [Ru]@UiO-66 demonstrated the ability to be recycled five times, showed no evidence of bimolecular catalyst decomposition, and was less prone to catalyst poisoning. These results demonstrate for the first time how the aperture-opening process resulting from linker dissociation in MOFs can be used as a strategy to synthesize host-guest materials useful for chemical catalysis. The aperture-opening encapsulation method offers insight into the effect of host-guest interaction in MOFs, which mimics outer-sphere interactions in enzymes. Future work will be focused on understanding these interactions and studying the activity of the encapsulated catalyst upon the manipulation of the environment in the outer-sphere.

Advances in Conjunctive Cross-Coupling Reactions

Gabriel Lovinger and James Morken

Enantioenriched organoboron compounds are of high value in organic synthesis due to their ideal balance of stability and reactivity, as well as their capacity to undergo enantiospecific conversion into functional groups ranging from alcohols and amines, to carbonyls and organohalides. This talk will discuss recent advances in conjunctive cross-coupling, a convergent and modular approach for the synthesis of enantioenriched alkyl boronic esters. Recent advances in the development of an enantioselective nickel-catalyzed conjunctive cross-coupling of alkyl electrophiles will also be presented.

Boston College Department of Chemistry

Eugene F. Merkert Chemistry Center 2609 Beacon Street

Chestnut Hill, MA, 02467 www.bc.edu/chemistry