Master Organic Chemistry Reaction Guide

Reaction Guide

The Reaction Guide gives individual descriptions, examples, and mechanisms of more than 185 of the most common reactions encountered in undergraduate organic chemistry. Only members can access all of the full pages.  Reactions highlighted in red are open-access.

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Comments

Comment section

35 thoughts on “Reaction Guide

  1. I’m a “printer”. I find wonderful resources (and this is website is one of the best – it’s incredible) and print them and carry them with me to study like flashcards. I wonder if there might be a “view/print” option that allows you to see the name of the reaction (like you have above) with just a tidy concise example/mechanism below it. That way someone could print off, say, reactions of alcohols. They would have a super fast review on their hands. With of course, the option of logging back on to click the reaction and get more detailed information (as you have it set up now). But mostly, I just need a memory jogger now and then, or confirmation that yes, the intermediate is a carbocation and not an oxacyclopentane, or no, I haven’t lost my marbles and gotten a set of electron pushing arrows in the wrong spot. They do go indeed from such and such to such and such.
    Thank you!!!!!!!!!!!!!!!

  2. This guide is great. One thing I was wondering though, would 1,2/1,4/1,6 addition to conjugated dienes go under reactions of alkenes and if so, do you think you’ll get around to posting that? Same for the Diels-Alder reaction. Thanks again, I greatly appreciate your efforts and passion for organic chemistry!

  3. Without your site I probably would not have gotten a B+ in Organic. I tell everybody to use your site. Hopefully I do better in organic 2. Thanks a million.

  4. check the page source code, hydrate formation on aldehydes and ketones are redirected to addition of LiAlH4 on ketones

  5. Hi James,
    Excellent contribution! But I wonder is there any pdf or somekind of print version which might help people use these reaction guide as flash cards or carry them?
    JK

  6. Hey Jim,
    I have to teach grade 11 AP chem this term and forgot all my orgo from 30 yrs back. The site gave me a great kickstart.
    Spaseeba from Kazakhstan.
    Mr. J

  7. Hey all great stuff here. Was just curious, why no reduction of carbonyls via desulfurization? I see you have Wolff-Kisher and Clemmenson, why not the 3rd?

  8. Hi James,
    I have been poking around your site looking for some helpful tips on figuring out the most reactive site on a molecule. Our professor expects us to memorize pKa’s of about 20 different acids, but I just can’t make them stick. I know to use resonance, inductive, etc., arguments, but sometimes those seem ambiguous. Here is an example of where I should be able to easily decide how the reaction progresses, but I can’t decide whether to protonate the oxygen, or the c=c. Do you have any tips?
    Example: Show the reaction of 4,4-dimethylpent-1-en-3-one with H3O+.

    1. Well, that compound in particular is an α,β-unsaturated ketone AKA an enone. The hyperconjugation of the C=O and C=C bonds stabilizes this class of compounds enough that it gets a section in textbooks, but the ultimate takeaway is that the same reactions that occur for alkenes and ketones still happen for enones. If you look at James’s mechanisms for the enone reactions, you can see that they’re all 1,4-additions. This gives you the clue that the alkene is where any nucleophile is going to attack. In aqueous acid, H3O+ would protonate the alkene, and H2O would initiate nucleophilic attack on the resulting positive charge. As a side note: the extra methyl groups on the other side of the enone are there to make it clear that there are no competing reactions going on there, by eliminating alpha hydrogens.
      But what if you didn’t have a collection of mechanisms to reference? You can use the same factors that gauge acidity to determine that there’s a charge gradient from the terminal alkyne (δ+) to the O (δ-). Although the following post concerns acidity, the arguments you mentioned, resonance, etc. can be applied here too. They may seem ambiguous, but they do have a clear hierarchy for the most part. As always, beware of exceptions, though I don’t see any in the case of your enone.
      https://staging.masterorganicchemistry.com/2010/09/22/five-key-factors-that-influence-acidity/

      1. Thanks for your thoughtful reply. I have found lots of resources for reactions of alpha-beta unsaturated ketones, but all of the reactions require basic conditions. I think the purpose for this question is to find the starting materials for the aldol reaction. I will have to read up on the reactions involving alpha-beta unsaturated ketones.

        1. I don’t think this will lead to an aldol reaction because hyperconjugation stabilizes the carbonyl such that enones don’t undergo 1,2-addition in the presence of most nucleophiles. I think Grignard reagents are the most common exception, though.

  9. I have found this site very very helpful at many points through my journey in Org 1 and 2, but now, towards the end of org 2 I am finding it less and less useful, which seems strange since there are more and more reactions. Why are there so few reactions of carboxylic acids? carboxylic acid chemistry is the core of org 2, not to mention biochemistry. It would be really really helpful if there were more of them. Also, I think there needs to be some consistency with where reactions are placed, if they are going from a type of molecule, they should all be grouped in that grouping, or maybe have two legends so reactions can be looked up based on their reactant or product.

  10. Could you add the Simmons-Smith reaction to this guide? We went over it in my Orgo 2 class and I was a little confused. Thanks!

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