Orgo 2 memorization?

[chillingpanda]

People say you're not suppose to memorize orgo to ace it, but what does that really entail? What I mean is how in dept should I be going for in order to learn the mechanism instead of "memorizing" it? For example, we're doing the reactions and synthesis that make ethers, like william ether synthesis, synthesis of epixodes...etc. What should I mainly focus on for that?

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[stickgirl390]

People say you're not suppose to memorize orgo to ace it, but what does that really entail? What I mean is how in dept should I be going for in order to learn the mechanism instead of "memorizing" it? For example, we're doing the reactions and synthesis that make ethers, like william ether synthesis, synthesis of epixodes...etc. What should I mainly focus on for that?

practice practice practice. Your textbook should have a million sample problems at the end of each chapter. Don't "memorize" anything, learn it! The best way to learn is to try a problem, get it wrong, and understand where you made a mistake. Rinse and repeat until you can do a problem all by yourself with no errors. If you have the answer key to your text, that is very helpful.

 

[kraskadva]

People say you're not suppose to memorize orgo to ace it, but what does that really entail? What I mean is how in dept should I be going for in order to learn the mechanism instead of "memorizing" it? For example, we're doing the reactions and synthesis that make ethers, like william ether synthesis, synthesis of epixodes...etc. What should I mainly focus on for that?

That entails learning what electrons like to do. All of orgo boils down to understanding what kind of personalities the elements have and which will steal or give up electrons.

When you hit the different synthesis stages in orgo, the only things you need to memorize are the reactants, i.e. Borane Tetrahydrofuran will take a carboxylic acid to an alcohol or a nitrile to an amine.
It's pretty much guaranteed that the synthesis problems you will get on the tests will not be in your book. But as long as you know how to move stepwise to build a compound, and remember which reactants will do what, you'll be fine.

 

[iqe2010]

I'm currently in ochem II, I barely got through the first part ha ha.

TBH, everything starts to look the same after a while. We're currently on alcohol reactions, and it all looks the same just different reagents.

The MCAT doesn't even cover most of this stuff. *sigh*

 

[mw18]

You have to memorize them. There isn't another way. I think the advice is to not JUST memorize them. They become much, much easier to memorize when you understand the why.

 

[Runner500]

You have to memorize them. There isn't another way. I think the advice is to not JUST memorize them. They become much, much easier to memorize when you understand the why.

I second this

 

[BunnyMan17]

Do practice problems until your eyes bleed and you internalize all the patterns. Orgo is all about the patterns

 

[aldol16]

I know that when we teach Organic II, we teach a lot of named reactions and you are expected to know and understand them. Too many pre-meds erroneously start with the name and memorize the steps of the reaction. A better way to do it is to look at the mechanism of some named reaction without thinking about the name first. And look to see what the reaction does. Each mechanism/reaction accomplishes a particular transformation and does it a certain way. If you can understand why and how it does it, then you would be able to use it on an exam without even knowing its name. Then after you understand how it works and why it works the way it does, then you can associate the name with it.

For instance, look at the Wolff-Kishner reduction. You start with a ketone. Then you make a Schiff base equivalent using a hydrazine. How does that work? Well, you'll need a strong base to pluck off protons from one of the nitrogens so that it can attack the carbonyl. After that, you need that strong base to pluck off protons from the other nitrogen so that you can protonate the alpha carbon and blow off nitrogen. Because of how it works, the hallmarks of a Wolff-Kishner reduction are obviously hydrazine and a strong base. You can thus directly reduce a carbonyl all the way down to an alkane without going through an alcohol intermediate. Draw the mechanism a few times and in the future, you'll know what to do when you see a carbonyl and a hydrazine.

Further, since you should now understand why the Wolff-Kishner reduction requires strongly basic conditions, you should also know when to use it - that is, when a substrate can tolerate basic conditions but not acidic conditions. For instance, if your substrate hydrolyzes in acid, then you can't use the Clemmensen reduction but rather have to use this method. Conversely, if you have a substrate that could potentially form an enolate and perform an intramolecular ring-closing reaction, then you can't use the Wolff-Kishner reduction because the strong base required would do that kind of enolate chemistry. So you would use the Clemmensen reduction instead.

 

[deleted738762]

I know that when we teach Organic II, we teach a lot of named reactions and you are expected to know and understand them. Too many pre-meds erroneously start with the name and memorize the steps of the reaction. A better way to do it is to look at the mechanism of some named reaction without thinking about the name first. And look to see what the reaction does. Each mechanism/reaction accomplishes a particular transformation and does it a certain way. If you can understand why and how it does it, then you would be able to use it on an exam without even knowing its name. Then after you understand how it works and why it works the way it does, then you can associate the name with it.

For instance, look at the Wolff-Kishner reduction. You start with a ketone. Then you make a Schiff base equivalent using a hydrazine. How does that work? Well, you'll need a strong base to pluck off protons from one of the nitrogens so that it can attack the carbonyl. After that, you need that strong base to pluck off protons from the other nitrogen so that you can protonate the alpha carbon and blow off nitrogen. Because of how it works, the hallmarks of a Wolff-Kishner reduction are obviously hydrazine and a strong base. You can thus directly reduce a carbonyl all the way down to an alkane without going through an alcohol intermediate. Draw the mechanism a few times and in the future, you'll know what to do when you see a carbonyl and a hydrazine.

Further, since you should now understand why the Wolff-Kishner reduction requires strongly basic conditions, you should also know when to use it - that is, when a substrate can tolerate basic conditions but not acidic conditions. For instance, if your substrate hydrolyzes in acid, then you can't use the Clemmensen reduction but rather have to use this method. Conversely, if you have a substrate that could potentially form an enolate and perform an intramolecular ring-closing reaction, then you can't use the Wolff-Kishner reduction because the strong base required would do that kind of enolate chemistry. So you would use the Clemmensen reduction instead.

I'm not surprised how great this post is coming from Mr. Aldol condensation.

 

[Saifa]

Organic chemistry was fun and games with the "you don't have to memorize anything if you understand it approach" until you realize your exam is going to have dozens of potential reagents scrawled above/below the arrows, at which point you rightfully ask "what the **** happened to not having to memorize anything???"

True, some reagents are simple enough that you may be able to visualize what they do by drawing a Lewis structure or something, but if you don't remember what "NBS" or "Lindlar cat." is and what it does, sorry dude.

 

[TheAppleJuice]

No, there is a lot of memorization that you can't get around, but you can't only memorize the reactions/reagents (and in fact memorization is the least of it). You need problem solving skills which come from intuition and practicing synthesis.

The saying is for people who got through gen bio, gen chem, and gen phys simply spending hours memorizing things without conceptually understanding anything. This is one reason orgo is such a weed out class, because it can't be done like this

 

[ciucia53]

I know that when we teach Organic II, we teach a lot of named reactions and you are expected to know and understand them. Too many pre-meds erroneously start with the name and memorize the steps of the reaction. A better way to do it is to look at the mechanism of some named reaction without thinking about the name first. And look to see what the reaction does. Each mechanism/reaction accomplishes a particular transformation and does it a certain way. If you can understand why and how it does it, then you would be able to use it on an exam without even knowing its name. Then after you understand how it works and why it works the way it does, then you can associate the name with it.

For instance, look at the Wolff-Kishner reduction. You start with a ketone. Then you make a Schiff base equivalent using a hydrazine. How does that work? Well, you'll need a strong base to pluck off protons from one of the nitrogens so that it can attack the carbonyl. After that, you need that strong base to pluck off protons from the other nitrogen so that you can protonate the alpha carbon and blow off nitrogen. Because of how it works, the hallmarks of a Wolff-Kishner reduction are obviously hydrazine and a strong base. You can thus directly reduce a carbonyl all the way down to an alkane without going through an alcohol intermediate. Draw the mechanism a few times and in the future, you'll know what to do when you see a carbonyl and a hydrazine.

Further, since you should now understand why the Wolff-Kishner reduction requires strongly basic conditions, you should also know when to use it - that is, when a substrate can tolerate basic conditions but not acidic conditions. For instance, if your substrate hydrolyzes in acid, then you can't use the Clemmensen reduction but rather have to use this method. Conversely, if you have a substrate that could potentially form an enolate and perform an intramolecular ring-closing reaction, then you can't use the Wolff-Kishner reduction because the strong base required would do that kind of enolate chemistry. So you would use the Clemmensen reduction instead.

This is a great post and I highly second it. My TA said "follow the electrons" during each weekly review session we had. I had a little trouble with nomenclature, so I made some flashcards to help me remember the difference between esters and ethers for example (idk for whatever reason it wasn't sticking at the time lol), as well as certain important reagents to know. I tried route memorization of reactions, but ultimately found this to be a waste of my time and I really wish I had spent more time understanding why and how the reaction does what it does.

 

[aldol16]

Organic chemistry was fun and games with the "you don't have to memorize anything if you understand it approach" until you realize your exam is going to have dozens of potential reagents scrawled above/below the arrows, at which point you rightfully ask "what the **** happened to not having to memorize anything???"

True, some reagents are simple enough that you may be able to visualize what they do by drawing a Lewis structure or something, but if you don't remember what "NBS" or "Lindlar cat." is and what it does, sorry dude.

Unfortunately, some reagents you will have to know, although any good professor will point these out in lecture or remind you on an exam. But you should really understand what these reagents do and how they do it. Otherwise, you'll be asked to do a synthesis and you'll be using strongly basic conditions when your substrate can't tolerate basic conditions. Understanding how a reaction works allows you to answer two types of questions - a forward synthesis where you're given the reagents and your own synthesis where you have to propose reagents to get from A to D. If you only memorize reagents, you'll probably do well on the first type but struggle on the second type because you don't really understand the specific conditions under which these reactions work. For instance, you'll have many oxidation/reduction type reactions in organic chemistry. But chemists don't just indiscriminately use Wolff-Kishner, Clemmensen, NaBH4, LiAlH4, MPV reductions, etc. to reduce a carbonyl - we don't just flip a coin to choose. Each reagent has its unique properties and appropriate circumstances under which you use them and to understand this, you must know how each one works.

 

[chillingpanda]

Thanks everyone for the great tips!

 

[wizzed101]

Unfortunately, some reagents you will have to know, although any good professor will point these out in lecture or remind you on an exam. But you should really understand what these reagents do and how they do it. Otherwise, you'll be asked to do a synthesis and you'll be using strongly basic conditions when your substrate can't tolerate basic conditions. Understanding how a reaction works allows you to answer two types of questions - a forward synthesis where you're given the reagents and your own synthesis where you have to propose reagents to get from A to D. If you only memorize reagents, you'll probably do well on the first type but struggle on the second type because you don't really understand the specific conditions under which these reactions work. For instance, you'll have many oxidation/reduction type reactions in organic chemistry. But chemists don't just indiscriminately use Wolff-Kishner, Clemmensen, NaBH4, LiAlH4, MPV reductions, etc. to reduce a carbonyl - we don't just flip a coin to choose. Each reagent has its unique properties and appropriate circumstances under which you use them and to understand this, you must know how each one works.

But that will never happen. They want to keep Ochem "hard." That is pretty much the only way to make it so at that level.

 

[aldol16]

But that will never happen. They want to keep Ochem "hard." That is pretty much the only way to make it so at that level.

That's not the only way to make it hard at that level. I can think of out of the top of my head several natural products whose syntheses can be grasped by a freshman organic chemistry student but would take a first-year graduate student two or three hours to come up with by him/herself. If your instructors keep Organic hard by testing on how much you can brute force memorize, they're teaching it wrong. I don't expect that from my students.

 

[wizzed101]

That's not the only way to make it hard at that level. I can think of out of the top of my head several natural products whose syntheses can be grasped by a freshman organic chemistry student but would take a first-year graduate student two or three hours to come up with by him/herself. If your instructors keep Organic hard by testing on how much you can brute force memorize, they're teaching it wrong. I don't expect that from my students.

Then will you be ok if tests are open book? You can go to any college in this country, pick a "hard" problem on an Ochem test and let students use their textbooks. I bet you anything the problem will not be "hard" anymore. Any college, any problem.

 

[aldol16]

Then will you be ok if tests are open book? You can go to any college in this country, pick a "hard" problem on an Ochem test and let students use their textbooks. I bet you anything the problem will not be "hard" anymore. Any college, any problem.

I know several professors who already do this. When I was an undergraduate, my organic exams were open book. The idea is that making you memorize reagents is pointless - you have to apply them.

Here's one question I like to ask: why do SN2 reactions have to occur via backside attack?

 

[wizzed101]

The nucleophile attacks the carbon at 180° to the leaving group, since this provides the best overlap between the nucleophile's lone pair and the C–X σ* antibonding orbital.

Some people are very good at this ^^

 

[aldol16]

Some people are very good at this ^^

My point stands. I know of several colleagues who use the open-book model for exams and I experienced it myself as an undergrad. Trust me, students don't get all the questions right just because it's open book. That's because we ask the questions at a high level. For example, you might know the reagents for a Diels-Alder, but using it intelligently set and convey stereochemical information for a particular need is the beauty of total synthesis. You might enjoy Classics in Total Synthesis. Most synthetic procedures can be understood by a freshman organic chemistry student. Yet, these syntheses took years to develop and several won Nobel Prizes.

 

[wizzed101]

My point stands. I know of several colleagues who use the open-book model for exams and I experienced it myself as an undergrad. Trust me, students don't get all the questions right just because it's open book. That's because we ask the questions at a high level. For example, you might know the reagents for a Diels-Alder, but using it intelligently set and convey stereochemical information for a particular need is the beauty of total synthesis. You might enjoy Classics in Total Synthesis. Most synthetic procedures can be understood by a freshman organic chemistry student. Yet, these syntheses took years to develop and several won Nobel Prizes.

But you still risk rewarding the wrong kind of students: those like myself. Can you write a closed book Ochem exam with neither synthesis nor reactions? The SN2 question is a good one, for example.

 

[JoeCaputo]

I think students over interpret what a professor means when they say "don't memorize". There is a lot you have to memorize, but you really just need to keep practicing. Do every assignment 3-4 times until it is second nature.

 

[YouEverHadOurSausages?]

I highly recommend flash cards for every type of reaction. It's the only time I've ever used them and they worked wonders for me.

 

[aldol16]

But you still risk rewarding the wrong kind of students: those like myself. Can you write a closed book Ochem exam with neither synthesis nor reactions? The SN2 question is a good one, for example.

My exams are long enough that you can't just go and look everything up in the textbook even if it's in the textbook in the first place. Critical thinking is emphasized. For instance, I might include a synthesis where all the reagents are given but you have to suggest a mechanism, which involves setting several stereocenters. Use of a chiral auxiliary in a Diels-Alder reaction is an example.

 

[WhittyPsyche]

It's a half truth. You have to memorize what a certain category of atoms/molecules do, and what certain kinds of solvents do. Then once you have that foundation, you use it to infer on reaction equation you've never seen before. After you're comfortable, it starts to feel obvious, like common sense. However, that initial understanding is crucial to build upon, and in a lot of ways that initial learning is essentially memorization from practice.


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[aldol16]

It's a half truth. You have to memorize what a certain category of atoms/molecules do, and what certain kinds of solvents do. Then once you have that foundation, you use it to infer on reaction equation you've never seen before. After you're comfortable, it starts to feel obvious, like common sense. However, that initial understanding is crucial to build upon, and in a lot of ways that initial learning is essentially memorization from practice.

It's like a language. When you first learned English, you had to memorize things. There was no getting around it. But once you have the fundamentals down, you can start reasoning out what, for instance, combinations of words mean and what certain words mean when used in conjunction with others.

 

[WhittyPsyche]

It's like a language. When you first learned English, you had to memorize things. There was no getting around it. But once you have the fundamentals down, you can start reasoning out what, for instance, combinations of words mean and what certain words mean when used in conjunction with others.

Exactly this!


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[Dagrimsta1]

Lewis took Orgo
Someone told Lewis that memorization in Orgo is a must
Lewis ended up getting a C in Orgo.
Don't be Lewis

 

[RogueBanana]

Memorization: Memorizing a particular reaction and only understanding it in the context of the molecule that the functional groups are located on.

Understanding: Memorizing mechanisms, functional groups and reactions. BUT understanding these reactions can take place on nearly any "base" molecule. Memorize functional groups and be able to apply the concepts relevant to them no matter what "base" molecule they are located on. Thus, you turn orgo into a game of Legos. Building things piece by piece, step by step, reaction by reaction.

Often times, especially in synthesis problems, multiple functional groups will be effected by certain step. IE. If you treat a molecule with multiple carboxyl groups with LiAlH, they will all be reduced. You must recognize that if you want to reduce only one of those groups, you must put a protecting group on the others.

There will be multiple "correct" ways to solve a synthesis problem, the more reactions you know, the less steps you will need to take to solve it.

Finally, realize that the principle reactions of the functional groups will hold true in almost all cases for a regular undergraduate class, as such, they will try to give you easy problems presented in a hard way. A common "trick" professors like to play in undergrad orgo classes is to give you a normal SN2 reaction but with a ring formation. They will give you a long carbon chain with a good nucleophile on one end, and a good electrophile on the other. The reaction would form a ring under the right conditions. (Lactone formation is a good example of this)

In research, things that should work on paper often don't, and a lot of our time is spent trying to figure out what does work and why. But that isn't gonna be a problem for you unless you make the bad choices I did and decide to pursue orgo beyond the requirements.

 

[chillingpanda]

I highly recommend flash cards for every type of reaction. It's the only time I've ever used them and they worked wonders for me.

How did you make your flashcards? Was it like you have a starting compound then the reaction and the mechanism on the backside? I've been using anki for a few of my classes with great results, and I have a surface pro so I can draw it and screen clip the drawings and paste into the card

 

[Coltuna]

Memorize what the reactions do and then do practice problem after practice problem after practice problem after practice problem after practice problem after practice problem until you could write your own test on the material.

 

[YouEverHadOurSausages?]

How did you make your flashcards? Was it like you have a starting compound then the reaction and the mechanism on the backside? I've been using anki for a few of my classes with great results, and I have a surface pro so I can draw it and screen clip the drawings and paste into the card

If I remember correctly, I just had the starting and ending materials of the reaction on the front, with the reagents on the back.

 

[chillingpanda]

Crappp. Literally got an 80% on the first exam, should've redid the problems from the back of the book more than once. Made tons of dumb mistakes. Feels bad man.

 

[YouEverHadOurSausages?]

Crappp. Literally got an 80% on the first exam, should've redid the problems from the back of the book more than once. Made tons of dumb mistakes. Feels bad man.

I got a 2/10 on my first quiz and a 70 on my first test. I was able to turn it around and finish with the highest grade in my class. Just keep at it and keep looking for new ways to improve.