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.
| Alkanes | ||
|---|---|---|
| Free radical chlorination [hν, Cl2] | Free radical bromination [hν, Br2] | Allylic bromination [NBS] |
| Alkenes | ||
| Addition of HCl | Addition of HBr | Addition of HI |
| Addition of H3O(+) | Chlorination [Cl2] | Bromination [Br2] |
| Iodination [I2] | Chlorohydrin formation [Cl2/H2O] | Bromohydrin formation [Br2/H2O] |
| Ether Formation [H+/ROH] | Oxymercuration [Hg(OAc)2/H2O] | Oxymercuration [Hg(OAc)2/ROH] |
| Hydroboration | Epoxidation [RCO3H] | Dihydroxylation [OsO4] |
| Dihydroxylation [KMnO4] | Cyclopropanation | Dichlorocyclopropanation |
| Ozonolysis (Reductive workup) | Ozonolysis (Oxidative workup) | Oxidative Cleavage [KMnO4] |
| Hydrogenation | Rearrangements (H shift) | Rearrangements (Alkyl shift) |
| Free Radical Addition of HBr | Sharpless Epoxidation |
| Alkynes | ||
|---|---|---|
| Deprotonation (acetylide formation) | SN2 with alkyl halides | Partial reduction (Lindlar) |
| Partial reduction [Na/NH3] | Hydroboration | Oxymercuration |
| Addition of HCl, HBr, or HI (once) | Addition of HCl, HBr, or HI (twice) | Hydrogenation |
| Ozonolysis | Oxidative cleavage [KMnO4] | Alkyne formation via elimination |
| Halogenation [Cl2, Br2, I2] | ||
| Substitution Reactions (SN2) [nucleophile in brackets] | ||
| Alcohol formation [HO(–)] | Alcohol formation [H2O] | Nitrile formation [CN(-)] |
| Thiol formation [HS(–)] | Ether formation [RO(–)] Williamson | Thioether formation [RS( –)] |
| Azides [N3(–)] | Ester formation [RCO2(–)] | Acetylide addition [RC≡C(–)] |
| Alkanes [Gilman reagents] | Alcohol formation [thru ether cleavage] | Ammonium salt formation [RNH2] |
| Substitution Reactions (SN1) [nucleophile in brackets] | ||
|---|---|---|
| Alcohol formation [H2O] | Ether formation [ROH] | Alcohol formation [ether cleavage] |
| Alkyl chloride formation [HCl] | Alkyl bromide formation [HBr] | Alkyl iodide formation [HI] |
| SN1 w/ rearrangement [alkyl shift] | SN1 w/rearrangement [hydride shift] | |
| Elimination Reactions | ||
|---|---|---|
| E2: Alkenes from alkyl halides | Alkenes from alcohols [strong acid] | Alkenes from alcohols [POCl3] |
| E1: Alkenes from alkyl halides | E1 with rearrangement [alkyl shift] | Hoffmann Elimination |
| Alkyne formation via elimination | E1 with rearrangement [hydride shift] | |
| Reactions of Organometallics | ||
|---|---|---|
| Grignard formation [alkyl halides] | Grignard formation [alkenyl halides] | Reaction of Grignards with acid [H+] |
| Addition of Grignards to aldehydes | Addition of Grignards to ketones | Addition of Grignards to esters |
| Reaction of Grignards with CO2 | Addition of Grignards to nitriles | Formation of organolithium reagents |
| Formation of Gilman reagents | SN2 with Gilman reagents | Addition of Gilman reagents to enones |
| Addition of Gilman to acyl halides | Heck Reaction | Suzuki Reaction |
| Stille Reaction | ||
| Reactions of Epoxides | ||
| Epoxide opening [basic conditions] | Epoxide opening [acidic conditions] | Epoxide opening [diol formation] |
| Epoxide formation [from halohydrins] | Epoxide formation [from alkenes] | Sharpless Epoxidation of alkenes |
| Reactions of Alcohols and Thiols | ||
| Deprotonation [alkoxide formation] | Protonation [onium ion formation] | Conversion to ethers [Williamson reaction] |
| Conversion to tosylates/mesylates | Conversion to alkyl chlorides [SOCl2] | Conversion to alkyl bromides [PBr3] |
| Oxidation to aldehydes [PCC] | Oxidation to ketones [PCC + others] | Oxidation to carboxylic acids [H2CrO4 + others] |
| Protection as silyl ethers | Thiol formation [SN2] | Thiol oxidation to disulfides |
| Reactions of Dienes | ||
| Diels–Alder reaction | Polymerization of dienes | |
| Reactions of Aromatics (Arenes) | ||
| Nitration [HNO3/H2SO4] | Chlorination [Cl2 plus catalyst] | Bromination [Br2 plus catalyst] |
| Sulfonylation [SO3/H2SO4] | Friedel Crafts alkylation [R-X plus catalyst] | Friedel Crafts acylation [RCOX plus catalyst] |
| Iodination [I2/catalyst] | Side chain oxidation [KMnO4] | Reduction of nitro groups |
| Reduction of aromatic ketones | Side chain bromination | Nucleophilic Aromatic Substitution (SNAr) |
| Aryne Formation (SNAr via arynes) | ||
| Reactions of Aldehydes and Ketones | ||
| Hydrate formation [H2O] | Cyanohydrin formation [CN(–)] | Reduction of aldehydes [NaBH4] |
| Reduction of aldehydes [LiAlH4] | Reduction of ketones [NaBH4] | Reduction of ketones [LiAlH4] |
| Grignard addition to aldehydes | Grignard addition to ketones | Acetal formation [ROH/H+] |
| Acetal hydrolysis [H3O+] | Imine formation [RNH2] | Enamine formation [R2NH] |
| Wolff-Kishner: reduction to alkanes | Clemmensen reduction to alkanes | Oxidation to carboxylic acid [H2CrO4 or KMnO4] |
| Keto-Enol tautomerism | Enolate formation | Aldol addition reaction |
| Alkylation of enolates | Wittig reaction: alkene formation | Thioacetal formation |
| Imine hydrolysis | Oxidation to carboxylic acids [Tollens] | Haloform reaction |
| Baeyer-Villiger Reaction | Aldol Condensation | Cannizarro Reaction |
| Reactions of Carboxylic Acids | ||
| Deprotonation [carboxylate formation] | Formation via Grignard and CO2 | Conversion to acid chloride [SOCl2] |
| Reduction [LiAlH4] | Fischer esterification | Decarboxylation [of β-keto acids] |
| Reactions of Esters | ||
| Reduction to aldehydes [DIBAL-H] | Reduction to alcohols [LiAlH4] | Hydrolysis to carboxylic acid [acidic] |
| Hydrolysis to carboxylic acid [basic] | Addition of Grignard reagents to esters | Claisen condensation |
| Transesterification [basic conditions] | ||
| Reactions of Acyl Halides | ||
| Conversion to esters [ROH] | Conversion to carboxylic acids [H2O] | Conversion to anhydrides [RCO2(–)] |
| Conversion to amides [RNH2] | Conversion to ketones [Gilman reagents] | Conversion to aldehydes [LiAlH(OtBu)3] |
| Reactions of α,β-unsaturated ketones [enones] | ||
| Michael reaction [conjugate addition of enolates] | Conjugate addition of Gilman reagents | Conjugate addition of other nucleophiles |
| Reactions of Amines and Amides | ||
| Dehydration of amides to nitriles [P2O5] | Hofmann rearrangement | Gabriel Synthesis of amines |
| Reductive Amination | Formation of Diazonium Salts | Reactions of Diazonium Salts |
| Amide Formation Using DCC | Amide Formation from Acid Halides | Curtius Rearrangement |
| Reactions of Nitriles | ||
| Addition of Grignard reagents to nitriles | Reduction to amines [LiAlH4] | Hydrolysis to carboxylic acids |
| Miscellaneous | ||
| Robinson annulation | Stork Enamine Reaction | Enamine Hydrolysis |
| Reduction of thioacetals to alkanes [Raney Ni] | Malonic Ester / Acetoacetic Ester Synthesis | Pinacol Rearrangement |
| Hell-Vollhard-Zolinsky Reaction | Wolff Rearrangement | Mannich Reaction |
| Beckmann Rearrangement | Oxidative cleavage of vicinal diols | Kiliani Fischer Synthesis |
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!!!!!!!!!!!!!!!
Thanks Jennifer – that’s something I’d like to do, just working for the moment on just getting the reactions up!
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!
thanks! I need to reorganize this page soon. If you look near the bottom, you’ll see a section on a,B-unsaturated ketones.
WOW! this site helped me understand those reaction clearly thanks a lot! EXCELLENT SITE!
Thanks, glad you find it useful.
The working link to the first one is
https://masterorganicchemistry.com/reaction-guide/free-radical-alkane-chlorination/
Helpful and timely
. Thank you.
Glad you’re finding it useful Judith!
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.
check the page source code, hydrate formation on aldehydes and ketones are redirected to addition of LiAlH4 on ketones
I can’t seem to access conversion to esters in the acid chloride section
I mean in the acyl halide section
Never-mind it was a problem with my browser
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
As a pdf it would be huge. Re: flashcards, we’re working on it, stay tuned!
The Staudinger reaction would be cool to have up here. Thanks!
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
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+.
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://www.masterorganicchemistry.com/2010/09/22/five-key-factors-that-influence-acidity/
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.
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.
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.
Which are the pericyclic reactions?