Cumulative Exams

Organic Cumulative Exam Topic for June 6, 2022:

JACS ASAPs from May 16–20, 2022

Readings: JACS ASAPs from May 16–20, 2022

Additional Readings: none

Graduate School Lesson: Read the literature and stay up to date with the state of the art in Organic Chemistry. Read broadly and read diligently. Learn how to other leaders in the field use fundamentals in physical organic chemistry to solve challenging problems in organic synthesis. Learn what’s trending and how to understand it and potentially incorporate it into your research as you think about your research challenges and grow as independent scientists.

Learning Goals:

• I expect the majority of this exam to be ‘do-able’ with the knowledge you’ve gained from your classes. Therefore, the exam will cover a range of topics and questions that may arise in a second-year literature seminar Q&A or in an ORP defense. This is not about specific memorization of very specific details within these selected manuscripts but broadly a chance for you to showcase the strength of your fundamentals.

On Exam Day: no additional notes allowed

Organic Cumulative Exam Topic for January 17, 2022:

The Chemistry of Professor Melanie S. Sanford

(POCC Lecture Jan 27, 2022)

Readings: Acc. Chem. Res. 2020, 53, 10, 2372–2383. https://doi.org/10.1021/acs.accounts.0c00471.

Additional Readings: citations within

The faculty of the Organic Division use cumulative exams as a tool to educate and test graduate students. Often, one of the topics includes the general body of work of a notable synthetic Organic chemist. Professor Melanie Sanford will be speaking at POCC (Philadelphia Organic Chemistry Club) this January. As such, we thought it would be fitting to cover her work over the years. Specifically, this cumulative exam will cover her fluorination chemistry.

Accounts of Chemical Research (ACR) is a journal that often provides an opportunity for groups who have made strides in a specific area of research to summarize their work and provide context. It is useful as a mini review on Professor Sanford’s work.

This cumulative exam will focus only on her work regarding fluorination chemistry and the work found in the attached ACR. See below the learning goals to focus your study.

Learning Goals:

• Who is Professor Melanie Sanford?

• Importance of developing fluorination methodology

• Fundamental differences between electrophilic and nucleophilic fluorination reagents (and being able to differentiate them)

• Draw mechanisms

• Interpret energy diagrams

• Explain with fundamental FMO theory or stereoelectronics why specific reactions work or do not work (overcoming challenges and limitations to reactions)

On Exam Day: no additional notes allowed

Organic Cumulative Exam Topic for July 2021:

Recent advances in Pd/NBE cooperative catalysis

Reading:

“Modular Entry to Functionalized Tetrahydrobenzo[b]azepines via the Pd/Norbornene Cooperative Catalysis Enabled by a C7-Modified Norbornene”

by Xin Liu, Jianchun wang, and Guangbin Dong

J. Am. Chem. Soc. 2021, ASAP

https://doi.org/10.1021/jacs.1c04575

Additional Readings:

"Structurally Modified Norbornenes: A Key Factor to Modulate Reaction Selectivity in the Palladium/Norbornene Cooperative Catalysis "

by Renhe Li and Guangbin Dong

J. Am. Chem. Soc. 2020, 142, 17859

(for those who want a bit more perspective)

The exam will be a closed book exam (calculators and model kits allowed). The intention is that you can pass this exam given the information we expect an organic chemist to know. You will not be asked to memorize any specific data or result in the paper.

This exam will have concepts in spectroscopy (specifically related to the molecules shown in this manuscript). But as always, other concepts regarding, transition metal catalysis, mechanisms (both organic and organometallic), and demonstrating concepts from physical organic chemistry will also be included.

• • •

*Hello Organic Cume-taker. I will be going over this exam on Monday, July 26^th at 11AM, room Beury 404. All the organic groups (broadly defined) and anybody taking this cume is welcome. Pizza at noon. –Daniel Kim*

• • •

updated: 7/2/2021

Organic Cumulative Exam Topic for January 2021:

Items of Chirality and a Special Case Study in Asymmetric Hydrogenation

Readings: Halpern, J. Mechanism and Stereoselectivity of Asymmetric Hydrogenation. Science 1982, 217, 401.

Additional Readings: Yoon, T. P., Jacobsen, E. N. Privileged Chiral Catalysts. Science 2003, 299, 1691.
Quasdorf, K. W., Overman, L. E. Catalytic enantioselective synthesis of quaternary carbon stereocentres. Nature 2014, 516, 181.

(Note: I'm more focused on the ideas of the Overman review versus the reactions found inside of them).

Homogeneous asymmetric hydrogenation remains one of the most common ways to deliver optically active materials to market. Attached is an important case study from Jack Halpern who studied homogeneous Rh-catalyzed asymmetric hydrogenations of enamides to amino acid analogs. You will also be asked to demonstrate your ability in using concepts from frontier molecular orbital theory & physical organic chemistry to justify and explain different stereochemical outcomes. Outside of the Halpern paper, this exam will not test you on your knowledge of organometallic transformations/mechanisms.

Learning Goals:

• You will be tested on various concepts in asymmetric catalysis (such as dynamic kinetic resolution vs kinetic resolution)

• Be able to describe and identify various types of chirality in organic molecules

• Interpret data from Jack Halpern’s Science paper

• Propose various mechanisms that generate a stereocenter

• Propose the origin of stereoselectivity

On Exam Day: you may have access to this paper and any other resources you want (papers, books, internet, models, calculators, etc.). Given the nature of having cumulative exams online, I have decided to provide you unlimited resources. However, I believe a well-prepared student should be able to answer these questions without additional resources. Your answers must be your own, especially open-ended questions. Credit will be awarded only to relevant answers.

updated: 1/12/2021