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Too Little? Too Much? Chapter 7 is just Right!

Chapter 7 in Karty’s book struck me as very unique when I first reviewed it. Initially, I considered it to be just an overview chapter that I could breeze through without much thought. After further review, I thought perhaps it covered too much material and would cause students to be confused rather than deepen their mechanistic understanding. As with any major curriculum change, I just had to teach it in class to determine the benefits.

Once I actually taught Chapter 7 in class, I realized how much I had underestimated its value. Coming from a traditional, functional group based approach to teaching organic chemistry, it seemed crazy to me to introduce students to every elementary step that the students would ever encounter all at once. Especially during the first semester. The text also introduces language to describe each elementary step that may initially seem odd to the average organic chemist. For example, I’ve always taught the E1 mechanism as a single mechanism rather than separating the individual elementary steps, heterolysis and electrophile elimination, into their own categories. What I discovered is that this initial focus on elementary steps proved valuable throughout the course as I could refer to them in any mechanism discussed after chapter 7. By introducing the 10 major elementary steps early, complicated mechanisms could be broken down into digestible chunks for the students. It increased the students’ understanding of mechanisms overall and improved their arrow pushing skills on quizzes and exams. I was most impressed with their ability to correctly add curved arrows to very long, complicated mechanisms and to identify the elementary steps by name, all by the end of Ch. 7!

The other thing I love about chapter 7 (and the book in general) is the emphasis placed on addressing common mistakes and overlooked questions. By color-coding the electron rich (red) and electron poor (blue) regions of molecules, students can more easily identify nucleophiles and electrophiles to determine the direction of electron flow. This emphasis on drawing curved arrows in the proper direction significantly reduced the number of “backwards arrows” drawn by my students. In addition, many of the textbooks that I have used previously gloss over seemingly minor details like spectator ions. We all know that they are commonly omitted from organic reactions, but students are always wondering, “what happened to the sodium ion?”. While it’s something that I’ve always discussed in my courses, I was happy to see it addressed in the textbook for additional reinforcement.

Chapter 7 is a truly unique and valuable chapter, and I’m so happy that I took the risk to change my approach to teaching organic mechanisms. With the new release of the 2nd edition of the book, the changes Karty made to Ch. 7 only serve to enhance student understanding. Additional emphasis has been added to address common mistakes before they become bad habits. There are also more “Connections” boxes with interesting tidbits to connect the lesson to everyday experiences. I’m looking forward to incorporating these new additions into my lessons. If you haven’t already, give Chapter 7 a chance and perhaps it will become your favorite chapter, too.

You can read Chapter 7 from the new Second Edition under the “Sample Chapter & TOC” tab at the top of the page.

-Dr. Anne Szklarski, King’s College
Click here to learn more about Dr. Szklarski

Organically Gaining Synthetic Expertise

I started teaching Karty’s textbook in my first full-time teaching position, and I am not looking back. At the end of each semester as I review my course plan and think about what worked that semester and what didn’t, I always notice new ways in which this textbook design is smart, student-centered, and ultimately makes my job easier. The way the textbook addresses synthesis problems is just the latest example. Karty devotes two chapters at strategic points in the book to teaching synthesis, but this is really just the start of how his design is perfect for this topic.

As an organic chemistry professor, one of the end goals that I set for my students is that they will be able to propose a multi-step total synthesis for a moderately complex molecule. This skill is one many organic professors strive for because it allows our students to showcase a broad understanding of a variety of reactions. To be proficient in this skill, students have to know a large number of organic transformations, and more importantly, they need to recognize the advantages and limitations for each. For example, if our goal is to synthesize a primary alcohol, we have to know that oxymercuration/reduction or acid catalyzed hydration are poor choices (these lead to secondary or tertiary alcohols), while hydroboration/ oxidation is a likely tool that will be used.

In my courses, I often reach Karty’s first organic synthesis chapter (Chapter 13) towards the start of the second semester (Organic II), so I largely ignore the concept of a multi-step synthesis until that point. For my students, this pace actually works out perfectly because when they return from winter break we get to take time reviewing their first semester reactions while putting them into the context of useful tools towards building molecules. This initial taste of synthesis also helps to reinforce the importance of the content the students are learning. They realize that the reactions they are seeing are not just there to fill pages of a textbook, but instead can be used in meaningful applications.

Teaching synthesis at the mid-point in organic chemistry can have some challenges. The biggest issue is that students have really only begun to learn the practical reactions that are useful in a multi-step synthesis. This limits the examples we can provide to reinforce the concept. However, with Karty’s text, students do get exposed to some of the more “interesting” transformations earlier. For example, in chapter 10 students see alpha alkylations and halogenations, practical applications of an SN2 reaction. This topic often shows up in the middle of Organic II if you follow a functional group approach. I find that by that first synthesis chapter there is actually a breadth of material to work with to begin building an understanding of complex syntheses. Rather than an introduction in functional groups one at a time, typically confined to one or two chapters, students see these functional groups in different settings at various points of the semesters. This helps to bridge the relationships between functional groups and students start to think of groups not just as a starting material or a product, but also as a useful intermediate.

Later in the semester, once the students have really built up their “organic toolbox,” we get to revisit the concept of synthesis again as a separate chapter and learn additional strategies to apply synthesis in practice. Karty’s approach to introducing synthesis through these two chapters is unique and I have found that this is an excellent approach to ease my students into the topic. I see a growing appreciation for the reactions the students are learning as we move through the semester. They enjoy the “break” of the synthesis chapters where the amount of “new” content is low. Instead of absorbing new reactions, they get to practice what they’ve learned already.

I think for most students, developing a multi-step synthesis will always be one of the toughest parts of an organic class. However, with cleverly timed introductions to this skill and reinforcement throughout multiple chapters as in Joel’s book, our students often surprise themselves with their synthetic expertise.

-Jamie Ludwig, Rider University

Click here to learn more about Prof. Ludwig

A New Semester, A fresh Foundation

As a new fall semester dawns, my mind turns inevitably to the fresh crop of students that will soon be struggling with Lewis structures containing many more atoms than they are accustomed to. Teaching at a community college brings some advantages, like having organic students that you have taught through both semesters of the general chemistry sequence, and thus they know what they should be prepared for in terms of new material. There are also challenges, like the students drawn back to the study of organic chemistry from other career paths with the goal of transitioning into a health profession. These students are often a few years removed from the study of chemistry and are starting from a different place than the first group. And finally, I will see a group of students from general chemistry courses taught by different instructors with their own individual points of view on the material and/or different textbooks. My experience is that switching to Joel’s text has gone a long way towards solving the student preparedness problems I have encountered.

This preparedness issue creates a daunting challenge for the beginning of the class – to ensure that everyone is up to speed and grounded in the information they will need to succeed as the course progresses. In my experience, many organic chemistry textbooks are ill-equipped to aid in tackling this problem. Often the first chapter is a re-iteration of every general chemistry idea that has any relevance to organic chemistry with each topic being a single section of the chapter. This approach fails for students further removed from their general chemistry studies as well as those who didn’t put in as much effort as they should have.

In this early stage of learning organic chemistry from Karty’s text, students have specifically commented on the effectiveness of section 1.6 (Strategies for Success: Drawing Lewis Structures Quickly) as helping them bridge the gap between material covered in general chemistry and what will be expected in organic chemistry. The Lewis structure discussion in a general chemistry book, for example, often focuses on molecules made up of 3-5 atoms with a clear ‘central’ atom. This concept does not transfer well to even simple organic molecules with multiple carbon atoms (let alone oxygen and nitrogen). The hints that Joel provides in section 1.6 related to how many bonds each commonly encountered atom is likely to have jump-starts students’ ability to begin visualizing structures of larger molecules. This gives students a boost of confidence and clarity as they proceed through the remainder of the chapter and other issues they need to be familiar with like formal charges, likely bond/non-bonding pair architectures and recognizing resonance contributors.

After completing the first chapter from this book I believe many more of my students are well positioned to tackle the issue of nomenclature, which will be the subject of my next post.

-Don Carpenetti, Craven Community College
Click here to learn more about Don Carpenetti

An Enlightening Experience

Three years ago, as a first-time teacher, I took over for the previous organic chemistry professor at our university, including the textbook he was using. It was one of the most popular books organized by functional groups. After surviving through my first-year teaching, I sensed that it was confusing mechanistically. Seeing how the reaction worked behind the picture was challenging and frustrating to students. Books organized by functional groups are like a dictionary organized by alphabet; it is organized and easy to look information up, but might not be the best or easiest way to learn. Throughout the book, mechanisms were interspersed among different chapters. Some reactions were given without mechanisms, just for memorizing purposes. This reinforced the biggest misconception in most students’ mind: that organic chemistry is all about memorizing.

Inspired by a friend who specialized in chemical education, I decided to look for a textbook organized more like the organic chemistry ACS exam study guide, which is more mechanistically based. After briefly going through a few books on my inherited shelf, Joel’s book caught my eye. I liked how the book was structured and decided to give it a try.  While working our way through the first semester, going into chapter 7 was definitely a life changing experience. I remember exactly how I felt at the moment the class and i started the chapter, “An overview of the Most Common Elementary Steps.” WOW, organic chemistry indeed can be taught like this! It was absolutely enlightening.  For a while I couldn’t calm myself down. Now all the complicated mechanisms can be broken down into building blocks. Just like how we can identify functional groups in a structure instead of individual atoms, we can identify elementary steps for all the complicated mechanisms. Students don’t have to memorize multi-step mechanisms from scratch anymore.

To me organic chemistry is about two things: electronegativity, and nucleophile attacking electrophile. I liked that the book emphasized asking students to identify electron rich and electron poor sites for each elementary step; which trains them to be sharp on identifying nucleophile and electrophile. This helped students to develop a much better chemical intuition and see that organic reactions are all part of a big game. All the memorization is based on logical patterns.  Throughout the rest of the book, I kept on asking students to identify elementary steps, nucleophiles and electrophiles. Students think it’s fun to be in class, and enjoy exploring mechanisms, either independently or under guidance, for new reactions.  To help students navigate the large quantities of reactions, I also gave them reaction maps and quiz maps that are organized through functional groups. This turns out to be very effective as they’ve already got the mechanisms down by then.

Overall, I am really thankful for Joel’s textbook and for his innovative method of teaching. It made organic chemistry teaching and learning a much more effective, easier, and fun experience for both teachers and students.

-Jing Hao, George Fox University
Click here to learn more about Prof. Hao

 

Steal This Idea

Interest boxes are my favorite part of textbooks. Admittedly, I have been only studying and teaching chemistry for about 20 years but every chemistry textbook that I have ever used always had the fun breakout boxes that told a fun and interesting chemistry story related to that chapter’s material. At first glance, they might not seem that important. I would argue the opposite; I think those “interest boxes” as Karty’s organic chemistry textbook calls them, are one of the most important parts of textbooks. Allow me to elaborate.

If you are reading this, you are probably just as biased as me, but chemistry is awesome. AWESOME! If you want to know how something works, you can’t get too far without knowledge of chemistry. It is also a really difficult subject in college and not exactly that easy to teach either. Chemistry is complicated… but of course it is when we are working on our understanding of things on the molecular level. That is our challenge as chemistry professors and instructors; we have this amazing and interesting subject, but to appreciate it properly you really need to have a deep understanding of complex issues first, and then the pieces can start to come together. That is where I would say the interest boxes come in.

I have been teaching organic chemistry for 10 years, and two of the best pieces of advice from a professor that stuck with me from when I was just a graduate student were

first, as a teacher you should always see what other people are doing and steal their ideas, and second, you should always have one fun and interesting thing to talk about every single lecture.

In my lectures, I try my best to always bring in at least one generally interesting topic to talk about that relates to the chemistry we are discussing that day, or to something we have learned previously. It serves to break up the lecture and provides moments where students can relax and think about what they are hearing a little more with less pressure to take notes. It also provides some really important context to what we are doing. Fifty minutes of organic chemistry goes by pretty fast for me, but I can recognize that if I spend all class doing curved arrows and reaction coordinate diagrams you start to lose the bigger picture; not necessarily of the chapter, but of the awesome world of chemistry they are getting access to with this new knowledge. I also give my students a chance to hear about what they want to know by asking them to submit questions. I take 15-20 minutes every Wednesday to talk about one of their questions. I have covered all sorts of things from why do onions make you cry (good for the acids/bases question) to why does mint make your mouth feel cold? This is where the first piece of advice from my long-ago professor  comes in; feel free to steal my idea. My students love it, it keeps me learning new things, and it is a good chance to relate things back to organic chemistry. It helps students stay interested and motivated to come in to organic chemistry every week. It also reinforces material and is a way to show them that they have learned something useful in their everyday life. It is more or less the professor bringing those interest boxes right into the classroom.

The Karty organic textbook is a great place to start. Each chapter generally has a few interest boxes that tell interesting stories or are great examples of modern research, like quantum teleportation or nanocars. They serve the same sort of purpose in the text: to break up the chapter and to show off something cool, or relate the reactions and concepts to something from day to day life. For better or worse, my students tend to skip them when reading chapters and doing homework, so I feel confident in bringing those examples right into the classroom without being redundant. It does cost some lecture time to do, but losing a little time that I could spend on the core material is ok when I know I am improving the overall classroom experience and their “buy in” to the world of chemistry.

So yes, honestly to me those small and colorful interest boxes are one of the most important parts of my teaching. They keep me interested, they keep the students interested, and they serve as an excellent bridge between molecules on the page and molecules in the lab or everyday life. I couldn’t imagine a book without them, nor could I imagine teaching in the classroom without them. Steal this idea!!

-Andrew Robak, Keuka College
Click here to learn more about Dr. Robak

 

Students are Doin’ it for Themselves

As several contributors to this blog have pointed out, Joel Karty’s text introduces biochemistry topics early in the course through supplementary sections at the end of most chapters titled, “The Organic Chemistry of Biomolecules.” Many instructors have lauded this early inclusion of biomolecular topics as a motivator for biology majors and pre-professional students; one that facilitates understanding of subsequent and current coursework in biochemistry and biology. In addition, the modular nature of these sections provides significant flexibility for instructors, allowing us to decide what to teach and when to teach it.

During my year-long organic course for chemistry majors, I skipped over the biomolecule sections in the first quarter with plans to return with a single biochemistry unit in the spring quarter. Needless to say, it didn’t quite work out that way. The active learning emphasis of the course (see my previous post titled  POGIL and Mechanisms are Natural Allies) slowed our progress, leaving us without adequate time for a biochemistry unit at the end. Instead, I decided to introduce beginning biochemistry topics through take home portions of hour exams. The biomolecular topics addressed in these assignments include chirality in biochemistry, pH and amino acids, and major classes of biomolecules. Since the reference sections of the Karty text were from early in the course, student’s anxiety is reduced toward the self-directed learning experience. Ultimately, with the strong foundation afforded by the course and the Karty text, the students had developed skills necessary to handle this material on their own.

By the time we approached later biochemical topics, such as aromaticity and DNA (14.12), and mutarotation of monosaccharides (18.14), it was apparent that there would not be enough time for a large biochemistry unit at the end of the course. Thus, these topics were fit into their respective chapters, or soon thereafter. For example, heterocyclic aromaticity can be a rather obscure topic without the application of DNA base pairing. Likewise, hemi-acetal formation seems rather pointless without discussing monosaccharide cyclization, and biomolecular polymers fit naturally in a discussion of polymers of all types (Ch26).

By incorporating biomolecular topics in multiple ways and formats, my students apply organic structure and principles in biomolecular systems, in a manner seamlessly supported by the Karty text. Skipping early biomolecule sections allows students to focus on the organic chemistry fundamentals at the beginning of the course. Later, self-directed learning provides an introduction to structure and acidity topics in biomolecules, while grabbing the interest of the students with a biochemistry concentration. The introductory nature of the early topics also provide both a review of fundamentals or organic chemistry, and a confidence boost for students. Further along in the course, biochemistry-oriented topics fit well with the organic content surrounding them, providing  natural pathways linking organic chemistry and biomolecular subject matter, and therefore leaving my students with a more substantial understanding.

-Kimberley Cousins, California State University, San Bernardino

A Racemization Revelation

In my experience, when students are writing a reaction mechanism, the most common error is to form a strong base under acidic conditions or vice versa.  I stress the importance of paying attention to reaction conditions in lecture, but the “function group” based textbook previously used at Western Washington University did not contain a section dedicated to explaining this concept.  Looking back, the old text did not even include a section about how to write a mechanism or correctly use “curved arrow” notation.  This is my first quarter teaching from Karty’s organic chemistry text, and I was pleased to find that there is a section dedicated to writing a reasonable reaction mechanism that addresses this common student error.

Chapter 8.6a explains the importance of taking reaction conditions into consideration when writing a mechanism.  It gives examples of incorrect mechanisms and then shows the student how to fix the mechanism to match the conditions given.  It then includes multiple in-text problems for the students to practice writing a mechanism under either acidic or basic conditions.  I knew this section of the text would be instrumental in reducing errors on exam questions about familiar reaction mechanism, but I wasn’t expecting how helpful it would be for students working through unfamiliar reactions.

Recently, I had a student who was a biological anthropology major come to office hours and she wanted to work through problems 8.37 and 8.38 with me.  These problems asked the student to draw a mechanism for the racemization of the alpha carbon under acidic and basic conditions.

Reaction

At this point in the quarter, my students had worked though many proton transfer reactions, but I had not specifically covered this reaction.  Previously, with the book organized by functional group, alpha carbon substitutions are not taught until the end of the third quarter.  So, I was expecting the student to struggle through this problem.  She started working though the base-catalyzed racemization.  At one point she wanted to introduce a hydronium ion to protonate the enolate.  She stopped herself and said, “Wait, that doesn’t make any sense, I’m using base.”  She correctly finished the mechanism and then looked at me for confirmation.  I was blown away!  Not only had she correctly transferred protons but she had stopped herself from committing the most common student error.  I told her that I was impressed, and that previous first quarter organic chemistry students would typically struggle with completing that problem.  It became clear to me then that including this concept in the textbook had led me students to a better understanding of reaction mechanisms and predicting the mechanism of unknown reactions.

I am more convinced than ever that by switching to Karty’s Organic Chemistry: Principles and Mechanisms, our students are actually learning organic chemistry and not just memorizing it.

-Written by Jennifer Griffith, Western Washington University