Alkyne Reactions

[estradiol9]

My TPR Organic Chem book only covered three reactions for alkynes:

- catalytic hydrogenation with a metal catalyst (Ni, Pd, or Pt) to an alkane
- hydrogenation using lindlar catalyst (CaCO3 or BaSO4) to cis-alkene
- reduction with sodium metal/liquid ammonia to trans-alkene

Are there any others that we should know involving alkynes?

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[BerkReviewTeach]

Alkynes are NOT tested on the MCAT. They have not been tested on the MCAT for the last twenty years. Alkenes and benzene were tested up until 2003, but not since then. None of these topics appear on the current AAMC checklist of topics. Study them if you really want to, but they aren't going to be on your exam.

Some people comment with a study them just in case perspective, and that's fine for them. But if they're not on the AAMC list and haven't been for nine years, it's not worth the time spent. If they appeared on a recent MCAT, there would be people posting complaints about it. They're not on the test and studying them is not a good use of time.

 

[estradiol9]

Alkynes are NOT tested on the MCAT. They have not been tested on the MCAT for the last twenty years. Alkenes and benzene were tested up until 2003, but not since then. None of these topics appear on the current AAMC checklist of topics. Study them if you really want to, but they aren't going to be on your exam.

Some people comment with a study them just in case perspective, and that's fine for them. But if they're not on the AAMC list and haven't been for nine years, it's not worth the time spent. If they appeared on a recent MCAT, there would be people posting complaints about it. They're not on the test and studying them is not a good use of time.

I noticed this. I looked at the list and noticed that only alkanes are listed under hydrocarbons. So we really don't need to know the alkene reactions either? My TPR book gives 10 reactions of alkenes so that would be nice if I don't need to memorize them.

 

[Forkit]

I noticed this. I looked at the list and noticed that only alkanes are listed under hydrocarbons. So we really don't need to know the alkene reactions either? My TPR book gives 10 reactions of alkenes so that would be nice if I don't need to memorize them.

I want to know the answer for this as well, please

 

[Integrated MCAT Course]

You won't be tested for reaction details from alkenes, alkynes, and aromatics on the MCAT. I keep them up at WikiPremed as 'optional'. I suggest folks just skim those sections if they are pressed for time. I think it's good to give a bit of attention to it, because that chemistry is an important for the overall conception, but if you are pressed for time, you can skip it. Whatever you do, don't stress over alkenes, alkynes, and aromatic reactions.

I know this is against the grain. Some MCAT books on their 10th edition haven't changed since the early nineties, so you can run into outdated material where there is no reasoning at all, simply editorial laziness. For my part, though, keeping them on my site follows from the teaching philosophy of an integrated curriculum, where concept items have relevance 'in themselves' but also 'for the rest'. I keep the reactions around because having them present to mind does help a person understand things like how NADH works or retinal, for example, and for the MCAT, the deeper your comfort goes with that material the better, the greater the coherence, and this is what I'm trying to convey as a teacher, a knowledge base that converses with itself. This is my own way, which I know works for my own students, but others have a different approach.

So maybe it's just stubbornness on my part to keep them at all. Honestly I go back and forth. I do feel that AAMC's decision to remove them from the test wasn't fully thought out. I believe giving them a bit of attention will benefit you on the test as long as you have the right perspective and don't spend a week remembering all the ins and outs of electrophilic aromatic substitution.

 

[BerkReviewTeach]

You won't be tested for reaction details from alkenes, alkynes, and aromatics on the MCAT. I keep them up at WikiPremed as 'optional'. I suggest folks just skim those sections if they are pressed for time. I think it's good to give a bit of attention to it, because that chemistry is an important for the overall conception, but if you are pressed for time, you can skip it. Whatever you do, don't stress over alkenes, alkynes, and aromatic reactions.

I know this is against the grain. Some MCAT books on their 10th edition haven't changed since the early nineties, so you can run into outdated material where there is no reasoning at all, simply editorial laziness. For my part, though, keeping them on my site follows from the teaching philosophy of an integrated curriculum, where concept items have relevance 'in themselves' but also 'for the rest'. I keep the reactions around because having them present to mind does help a person understand things like how NADH works or retinal, for example, and for the MCAT, the deeper your comfort goes with that material the better, the greater the coherence, and this is what I'm trying to convey as a teacher, a knowledge base that converses with itself. This is my own way, which I know works for my own students, but others have a different approach.

So maybe it's just stubbornness on my part to keep them at all. Honestly I go back and forth. I do feel that AAMC's decision to remove them from the test wasn't fully thought out. I believe giving them a bit of attention will benefit you on the test as long as you have the right perspective and don't spend a week remembering all the ins and outs of electrophilic aromatic substitution.

This couldn't have been stated any better. I want to second two really important points made here. (1) Alkene chemistry is still possible as a biochemistry topic (hydrogenation of an unstaurated fat using FADH2 or dehydration to generate a pi-bond). (2) There is some carry over effect from alkene chemistry to other topics, so a very basic mechanstic understanding can help explain other material.

There are certain alkene reactions that are a complete waste to study (ones with no biological correlation), but knowing E2 for instance is quite helpful when understanding the Hofmann Elimination (a testable topic according to AAMC) because it's a special case of an E2. Use your common sense when looking at your review materials. If they explain why the alkene reaction is good to study, then it's probably a conscientious choice by the author and/or editor to keep it there. If it's there because an editor failed to remove it when the test changed, then you should take that with a grain of salt.

Lastly, and most importantly, it's always a good idea to cross-reference AAMC to verify what topics can be tested.

 

[mehc012]

I didn't really say anything worthwhile here...just a little surprised/disappointed that alkene reactions aren't on the test. I guess a lot more of chem is covered under 'organic' than I had thought, because I was thinking of those reactions as the foundation of everything else I learned in orgo! Looking over the MCAT subject list, I don't see much actual orgo, which is disappointing, but I guess it's that much less to review!