Reaction Guide

by James

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 Alkenes Alkynes Substitution (SN2) Substitution (SN1)
Elimination Reactions Alcohols and Thiols Organometallics Epoxides Dienes
Aromatics (Arenes) Aldehydes and Ketones Carboxylic Acids Esters Acyl Halides 
α,β-unsaturated alkenes
Amides  Nitriles  Miscellaneous


Alkanes
Free radical chlorination [hν, Cl2] Free radical bromination [hν, Br2] Allylic bromination [NBS]

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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

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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]

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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]

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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]

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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]

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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

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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

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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

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Reactions of Dienes
Diels–Alder reaction Polymerization of dienes

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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)

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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 [H2CrOor 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

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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]

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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]

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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]

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Reactions of α,β-unsaturated ketones [enones]
Michael reaction [conjugate addition of enolates] Conjugate addition of Gilman reagents Conjugate addition of other nucleophiles

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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

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Reactions of Nitriles
Addition of Grignard reagents to nitriles Reduction to amines [LiAlH4] Hydrolysis to carboxylic acids

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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

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{ 22 comments… read them below or add one }

Jennifer Zahren December 20, 2011 at 6:01 pm

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!!!!!!!!!!!!!!!

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james December 23, 2011 at 4:57 pm

Thanks Jennifer – that’s something I’d like to do, just working for the moment on just getting the reactions up!

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Ganesha February 27, 2012 at 1:45 am

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!

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james February 27, 2012 at 5:29 am

thanks! I need to reorganize this page soon. If you look near the bottom, you’ll see a section on a,B-unsaturated ketones.

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E March 15, 2012 at 9:48 am

WOW! this site helped me understand those reaction clearly thanks a lot! EXCELLENT SITE!

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james March 15, 2012 at 12:22 pm

Thanks, glad you find it useful.

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Marina April 20, 2012 at 7:16 pm
Judith April 24, 2012 at 11:11 am

Helpful and timely
. Thank you.

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james April 26, 2012 at 8:17 pm

Glad you’re finding it useful Judith!

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Md2be August 6, 2012 at 7:39 pm

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.

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Rajarshi Banerjee November 7, 2012 at 8:32 am

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

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Rajarshi Banerjee November 20, 2012 at 2:15 am

I can’t seem to access conversion to esters in the acid chloride section

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Rajarshi Banerjee November 20, 2012 at 2:15 am

I mean in the acyl halide section

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Rajarshi Banerjee November 20, 2012 at 2:25 am

Never-mind it was a problem with my browser

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JK January 25, 2013 at 11:51 am

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

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james January 25, 2013 at 3:56 pm

As a pdf it would be huge. Re: flashcards, we’re working on it, stay tuned!

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Thomas Peterson April 2, 2013 at 1:45 am

The Staudinger reaction would be cool to have up here. Thanks!

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Larry Jackson January 13, 2014 at 9:42 am

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

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Audrie Dugger May 2, 2014 at 11:51 am

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+.

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Mohammed Sharif May 4, 2014 at 7:32 pm

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.

http://www.masterorganicchemistry.com/2010/09/22/five-key-factors-that-influence-acidity/

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Audrie Dugger May 4, 2014 at 9:09 pm

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.

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Mohammed Sharif May 5, 2014 at 2:07 am

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.

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