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Making Molecules
@makingmolecules.com
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Making molecules - trying to explain chemistry one page at a time.

One page summaries and more wordy descriptions found at:
https://www.makingmolecules.com
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This #ChemEd #Chemistry #ChemSky is a stopgap. It wasn't made for MakingMolecules.com (there is no blog post (& different colours)). It wasn't written for students but was written to jog my memory (guess what I'm doing this week is?).
Disclaimer done! I hope someone else finds it useful.
Enjoy?
This is a quick recap on the fragmentation of peptides in an electrospray ionisation ESI mass spectrometer and a list of the common amino acids with some useful information about them.
September 8, 2026 at 8:40 AM
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The accompaniment to the last #Chemistry #ChemEd #ChemSky summary is now online at:
www.makingmolecules.com/blog/sigmatr...
The blog version contains more examples & talks you through the chemistry instead of just giving the pictures (bsky.app/profile/maki...).
Anyways, I hope it is useful.
Enjoy
Pericyclic Reactions: Sigmatropic Rearrangements — Making Molecules
This summary covers the most common [3,3]-sigmatropic rearrangements, the (oxy)-Cope rearrangement and the Claisen rearrangement, along with many of its variants. The rearrangements share a motif with...
www.makingmolecules.com
August 25, 2026 at 8:50 AM
makingmolecules.com
The next #ChemEd #Chemistry #ChemSky 1-page intro covers common [3,3]-sigmatropic rearrangements. Lovely reactions that are a nice way to form C-C bonds with good control of stereochemistry from readily formed precursors. As always, it's just an intro, no orbitals & no Woodward-Hoffmann. Enjoy.
This one-page summary looks at [3,3]-sigmatropic rearrangements. It starts by giving a quick run down of the naming convention (where the [3,3] or [i,j] nomenclature comes from. There is then an attempt to have one diagram cover all the common [3,3]-sigmatropic rearrangements such as the Cope, anionic oxy-Cope, Claisen and a host of modified Claisen rearrangements. This also gives a quick look at the chance of controlling the stereochmistry. Then there are examples of the anionic oxy-Cope rearrangement, the Johnson-Claisen and the Ireland-Claisen rearrangement. Hope you all like it.
August 11, 2026 at 8:36 AM
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As promised in the previous #ChemEd #Chemistry #ChemSky post, I have written a more wordy/detailed overview of 1,3-dipolar cycloadditions. It is available below:

I stress it is still an introduction but allows me to words/explanation than I can on a one-page summary.

Hope it is useful, enjoy.
July 28, 2026 at 8:40 AM
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This #ChemEd #Chemistry #ChemSky summary introduces 1,3-dipolar cycloadditions. It builds on the Diels-Alder 1 pagers & is another [4+2] cycloaddition but gives 5-membered rings. It is only an intro. More details will be on makingmolecules.com as soon as I've typed up my notes. Enjoy!
A one page summary of 1,3-dipolar cycloadditions. It starts with an introduction covering the general reaction and classifying 1,3-dipoles as either linear or bent. There are then four examples; nitrile oxide-alkene cycloadditions, nitrone-alkene cycloadditions, azide-alkyne cycloadditions and azomethine ylide cycloadditions (my favourite). The discussion of the azide reaction mentions the original pericyclic reaction and the catalysed variant that won the Nobel Prize.
July 14, 2026 at 8:39 AM
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#ChemEd #Chemistry #ChemSky summary looks at modifications of the Diels-Alder reaction. It includes IMDA (tie the ends together), HDA (swap one (or more) carbons out) & IEDDA. It mentions the old explanation for LA catalysis (the more modern explanation is at makingmolecules.com/blog/da-like...)
A summary of modified Diels-Alder reactions. It starts with the general reaction scheme showing the control of relative stereochemistry and the normal electronics. There is then a quick look at how you can alter the electronics (frontier molecular orbitals) to change the reaction (acceleration or inverse demand). Then there are four examples: a Lewis acid accelerated reaction with improved regioselectivity; an intramolecular Diels-Alder reaction (IMDA) where the two reactants have been tied together; a hetero-Diels-Alder reaction (HDA) where one carbon has been replaced by an oxygen atom; a bonus intramolecular hetero-Diels-Alder reaction just to show you string these things together and then an inverse electron demand Diels-Alder (IEDDA) where the dienophile is electron rich and the diene electron poor. More information can be found at https://www.makingmolecules.com/blog/da-like-reactions
June 16, 2026 at 8:54 AM
makingmolecules.com
My 1st #Chemistry #ChemEd #ChemSky summary on pericyclic reactions (more to follow) & it is on the Diels-Alder reaction. This is a fantastic reaction but I only cover the basics. Bond formation, regioselectivity (very simplistically) & a comment on exo vs endo. No Woodward-Hoffmann rules.
Enjoy.
A one page summary of the Diels-Alder reaction. This is just the basics and only covers a general reaction showing which bonds are made. Then gives a superficial explanation of regiochemistry followed by comments on endo vs exo selectivity. For more details see https://www.making molecules.com
June 2, 2026 at 8:36 AM
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As promised, a #ChemEd #Chemistry #ChemSky summary introducing enamines as enolate equivalents. It's only an intro so covers formation + 3 reactions. No regio- or stereoselectivity even though they're fun. I did include the catalytic cycle from enamine organocatalysis as people expect it. Enjoy.
A summary covering the simple alkylation of enamines (or enamines acting as enolate equivalents). It shows the general reaction along with the mechanism for the formation of enamines and then the mechanism for their alkylation. There is a summary of three reactions, alkylation, Michael or conjugate addition and the aldol reaction. The mechanism for enamine organocatalysis is also included as I'd be daft not to these days.
May 12, 2026 at 8:29 AM
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After enols & enolates, here's a #ChemEd #Chemistry #ChemSky on enolate equivalents. These allow control of selectivity & permit stereoselective enolate chemistry (something I love & will eventually write a summary on). Here is formation & aldol-like reaction. Enamines will get their own summary.
A summary covering some simple enolate equivalents. It looks at the formation of lithium enolates with LDA and shows the use of this reagent in the aldol reaction. Then there are the silyl enol ethers and their use in a Lewis acid activated aldol-like reaction. Finally, there are the wonderful boron enolates. And, you guessed it, their use in an aldol reaction. Next summary will have enamines.
April 28, 2026 at 8:55 AM
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No #ChemEd #Chemistry summary this week as the Analytical Science team was unleashed for a night of science, chemistry and fun. Big thanks to Brad and Daisy.
One very cold flower about to meet its doom Me not burning paper Daisy, Brad and my good self before all the fun starts
April 22, 2026 at 9:02 AM
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Breaking radio silence with 2x #ChemEd #Chemistry #ChemSky summaries of aldol-like rcts. These are just lists of reactions without the explanation of the last couple of summaries. One tries to include mechanisms. More a stop gap than anything else.

Hopefully, someone will find them useful. Enjoy.
A summary of aldol-like reactions, listing the most common examples found in many UG courses. There is an attempt to add some mechanisms to this, but not much. Not much in the way of explanation either. It is just a list! A summary of aldol-like reactions, listing the most common examples found in many UG courses. It is purely a list and not very exciting. Might be a revision aid. Might not (it was a stop gap as I was too busy to put together proper summary!).
April 14, 2026 at 8:49 AM
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Having introduced the aldol, here is a #ChemEd #Chemistry #ChemSky summary of the more common named variants. They're all the same reaction (just the electrophile/nucleophile changes; see reply). The mechanism is the same. Don't let the names mislead you. Hopefully it is useful to some.
Aldol-like reactions. All of these involve a stabilised anion adding to an electrophile, either a carbonyl group or an iminium ion. It covers the general mechanism and then gives examples of the Claisen & Dieckmann condensations (enolate adding to an ester. Only difference is if they are attached to each other). The Mannich reaction (enol adding to iminium species) and the Henry reaction (or nitro-aldol. A nitro stabilised anion adding to an aldehyde)... wow autocorrect hates chemistry after all these years and many additions to the user dictionary. I almost understand why some students switch it off.
March 24, 2026 at 7:54 AM
makingmolecules.com
The obvious next post after looking at enols/enolates is the aldol reaction. The aldol reaction is an impressive beast used by both nature and chemists. This #ChemEd #Chemistry #ChemSky summary is just the intro. There will be more over the coming weeks.
I hope UG enjoy this!
A summary or introduction to the aldol reaction. It shows the general reaction with both the aldol addition and the aldol condensation. This is followed by the curly arrow mechanism for the base-promoted aldol addition and the base-promoted aldol condensation. After that, there is, of course, the acid-catalysed version. Finally, I mention the crossed or mixed aldol and allude to the fact that selectivity can become an issue.
March 10, 2026 at 7:45 AM
makingmolecules.com
Enolates (& their equivalents) are one of the cornerstones of many a good synthesis. So here is a #Chemistry #ChemEd #ChemSky intro to their formation & general reaction. More details on the aldol reaction & enolate equivalents will be in subsequent summaries.
Enjoy.
A one page summary covering the formation and a couple of basic reactions of enolates (more reactions, like the aldol reaction will come in subsequent summaries). This is divided into three boxes. 1) Formation by deportation, including a brief discussion of regiochemistry in non-symmetric ketones. 2) A cartoon of the general reaction of enolates (reaction at the alpha position). 3) some useful examples of reactions that don't totally follow my generalisation.
February 24, 2026 at 7:36 AM
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The 1st of a few #ChemEd #Chemistry #ChemSky summaries related to enols/enolates/etc. This one covers keto-enol tautomerization and two reactions of enols. As always, it is just meant to cover the basics. It is a summary to refresh/support students' memories. As such, I hope it is of some use.
A summary of the formation of enols or keto-enol tautomerization and then two reactions of enols. There are four boxes of information. The first shows the curly arrow mechanism for both the acid and base catalysed formation of enols. The second box looks at the stability of the enol. Then we turn our attention to the bromination and nitrosation of an enol. THe mechanism is the same for both and hopefully reinforces some basic principles.
February 10, 2026 at 7:22 AM
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The obligatory summary of a summary and a table of E1 vs E2 vs Sn1 vs Sn2. Hopefully, this is of use to some, but if I'm brutally honest, it was just a quick stop gap while I work on more fun #ChemEd #Chemistry #ChemSky summaries (currently writing ones on cycloadditions and rearrangements).
Cheers
The classic table of E1 vs E2 vs SN1 vs SN2. Hopefully it is useful in giving UG students an idea of what mechanism might be in operative and answering some of those annoying exam questions (reality sucks, and it is highly likely that multiple mechanisms will be operating at the same time!).
January 27, 2026 at 7:52 AM
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The obvious follow-up to SN1/SN2 substitution is a #ChemEd #Chemistry #ChemSky summary on E1/E2 elimination. This summary only looks at E1/E2 & not fun like E1cB. More detail is www.makingmolecules.com/blog/elimina.... Enjoy (& yes a summary of which mechanism operates is coming next week). Enjoy
A summary of the first two eliminations that students tend to encounter, E1 and E2. It gives an overview of the two mechanisms. The first box shows a general elimination reaction and shows the various products that can be formed. The second box highlights some of the missing information from this summary and where it can be found (such as https://www.makingmolecules.com/blog/eliminations) Box 3 is E1 elimination with mechanism, energy profile, some orbitals & a discussion of regio- and stereoselectivity. Box 4 is the same for E2 elimination.
January 20, 2026 at 7:31 AM
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Today's #Chemistry #ChemEd #ChemSky summary is SN1/SN2 substitution. I waited until 46th summary to cover this as I don't think it's as important as the chemistry of the carbonyl group (but is invariably introduced 1st in textbooks 🤷‍♂️go figure). More info www.makingmolecules.com/blog/substit... enjoy
A summary of substitution at a saturated carbon. An introduction to SN1 and SN2. Two boxes show each overall reaction + rate law. Then give a simple energy diagram/reaction profile for each followed by the curly arrow mechanism. In the final box there are 6 factors that influence which mechanism is in operation (structure of the substrate and its effect on the stability of carbocations; leaving group ability, nucleophile strength and the solvent). Enjoy.
January 13, 2026 at 7:30 AM
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A contentious #ChemEd #Chemistry #ChemSky summary covering rates of reaction. It is the textbook version & is wrong if you understand kinetics ;) I'll add references showing why as a reply. It's here as most UG still learn it. Hopefully it is useful & doesn't cause too many misconceptions
A summary of the rates of reaction as found in textbooks (another way of saying, it is a gross simplification that is incorrect). Useful (hopefully) at the beginning of a student's study of mechanisms.
January 6, 2026 at 7:27 AM
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The last MakingMolecules #Chemistry #ChemEd #ChemSky of the year, but what a post, an org chemist introducing rates of reaction with collision theory! The pool analogy is shaky/orientation is important than direction/frequency not numbers). It's a vital topic but find a physical chemist for details.
A rough introduction to collision theory. Simplistically, collision theory treats molecules as hard spheres and says they will react if they hit each other with sufficient energy and in the correct orientation. The energy is required to overcome activation barrier. There is an analogy to pool and that you can think about trying to pot a ball. Needs two balls to hit, needs to have the correct energy and need them to be orientate correctly so that the ball goes in the pocket (but I'm avoiding saying direction as that is incorrect and causes confusion). TO accelerate a reaction you can increase the concentration as this increases the frequency of reactions. You can heat them up, the more they move the higher the frequency of collisions. The hotter the molecules, the more energy and the more chance of having sufficient energy. Or you could add a catalyst and this lowers the amount of energy the molecules require by changing rhetorical reaction pathway.
December 2, 2025 at 8:02 AM
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After 2 months of aromatic chem, here is something a little different (but not that different) & a #Chemistry #ChemSky #ChemEd summary on conjugate or 1,4- or Michael additions.
To sound like a stuck record, it is aimed at UG with only the general mechanism & brief notes on regioselectivity.
Enjoy.
A one page summary of conjugate additions. It is split into four sections. The first is the overall transformation with a list of the general structures that can participate in conjugate additions. The second section is a general formula. It covers the main steps but is a little vague on the proton transfers (like most organic chemists). Next there is a brief look at regioselectivity and what factors influence 1,2-addition versus 1,4-addition. It is not in depth but gives pointers. Finally, there are some examples.
November 25, 2025 at 7:22 AM
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The last nucleophilic aromatic substitution #Chemistry #ChemEd #ChemSky summary is a summary of the previous summaries. It shows 4 mechanisms of nucleophilic aromatic substitution including classic substitution, aryne intermediates, ionic & radical substitution of diazonium salts. Hope it helps.
A summary of the different methods for nucleophilic aromatic substitution. This includes the displacement of an activate leaving group (such as a fluoro derivative), the substitution of a halide through the formation of an aryne intermediate, and two mechanisms for the substitution of diazonium salts; either through an ionic mechanism or a metal mediated radical substitution.
November 18, 2025 at 7:38 AM
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With stunning originality & a certain amount of flare, I give you Nucleophilic Aromatic Substitution 3. A #ChemEd #Chemistry #ChemSky summary discussing substitution via aryne intermediates. It is pitched at #UG. More detail/references at www.makingmolecules.com/blog/benzyne
Hope it is useful
Enjoy
Another summary on nucleophilic aromatic substitution. In the first box, it shows that elimination can form an aryne that allows addition to occur. Overall, this results in substitution. The second box gives the mechanism and shows that two products can be formed depending on which end of the aryne the nucleophile adds. The third box shows a crude/simplified view of aryne structure while the final box shows one way of explaining regioselectivity (a more modern approach exists and there is a link to the appropriate paper).
November 11, 2025 at 7:45 AM
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The second #ChemEd #Chemistry #ChemSky summary on nucleophilic aromatic substitution. This time it covers the formation & use of diazonium salts. The substitution mechanism is either ionic or radical depending on the nucleophile.

Good(ish) with paracyclophane (honest)!

Hope this is useful.
Enjoy
A summary of nucleophilic aromatic substitution using diazonium salts. There is a summary of the most common transformations (phenols, halides, nitriles and a reduction). There is a curly arrow mechanism of diazonium salt formation. Finally, there is the mechanism of ionic substitution and the radical substitution.
November 4, 2025 at 7:23 AM
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After 3 #Chemistry #ChemSky #ChemEd summaries on electrophilic aromatic substitution, we move to the nucleophilic variant SNAr (surprise).
Not as common (due to structural limitations), but equally useful. Next week, the same reaction but with diazonium salts.
Hopefully no silly mistakes this time!
A one page summary of nucleophilic aromatic substitution. The first box introduces the transformation. The second is the general addition-elimination mechanism. The third looks at the importance of substitution patterns and the last box gives potential useful substituents and reagents.
October 21, 2025 at 6:53 AM