Making Molecules

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.

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 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.

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.

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!).

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

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.

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

Probably the same textbook that I actually bought twice (with my own money, and considering the number of 'freebies' I got from reps over the years that is saying something!)

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.

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

I have posted an erroneous summary for 2 (v. poor) reasons:
1) It agrees with the textbooks, so is what most undergraduates are taught (& that is the point of these summaries) &;
2) I haven't had a chance to update it even though it is several years old (writing new summaries instead).

For those interested in an intro to rate-determining states (replacing Rate Determining Steps) see
ChemPhysChem 2011, 12, 1413 (doi.org/10.1002/cphc... (behind a paywall))
or
Chem Soc Rev 2025, 54, 9145 (doi.org/10.1039/D4CS...)

'Enjoy' (but not too much as it isn't synthetic/organic chemistry)

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.

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

My employer (a certain large dairy co-op) might have few very good examples of them! The ones I know will certainly find all the mistakes I’ve made.

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.

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 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.

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 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.

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.

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).

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

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.

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 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.

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 summary of electrophilic aromatic substitution. This really is the barebones - all it covers is the general mechanism, examples of the most common reactions and activation & directing effects. This is basically a revision sheet.

Anyone for a summary of a summary?
After two weeks of #ChemEd #ChemSky #Chemistry summaries on electrophilic aromatic substitution here, by popular demand, is one chart that covers just the basics.
Enjoy.

More electrophilic aromatic substitution. Last week was the general reaction, today covers (de)activation & directing effects.
It is a #UG simplification so no discussion of inductive effect vs hyperconjugation etc (or the transannular effect). Enjoy #ChemEd #Chemistry #ChemSky

A summary of electrophilic aromatic substitution. There are six boxes. The first gives the general reaction and why it is different to addition to an alkene. The second gives the general curly arrow mechanism. After that it is a look at specific examples: bromination, nitration, sulfonation, Friedel-Crafts alkylation and Friedel-Crafts acylation. If you want more detail of the mechanisms of activation of the electrophiles read https://www.makingmolecules.com/blog/electrophilic-aromatic-substitution

Here's a #ChemEd #Chemistry #ChemSky summary of electrophilic aromatic substitution. As an ex-[2.2]paracyclophane chemist, this is a reaction dear to my heart.
Here is just the basic mechanism aimed at UG (the mechanisms for electrophile activation are www.makingmolecules.com/blog/electro...).
Enjoy

A summary of asymmetric hydroboration under either substrate control or pinene reagent control. The first box shows simple hydroboration. The second box shows an example of stereoselective hydroboration of a chiral cyclic molecule or substrate control. Then there is a look at stereoselective hydroboration of acyclic alkenes with an allylic stereocentre. Finally, there is reagent controlled hydroboration using pinene derived reagents to control the enantioselectivity of hydroboration.

These #ChemEd #Chemistry #ChemSky summaries target early UG & the basics. Except when they don't. Here is a follow-up to anti-Markovnikov addition summary & a look at asymmetric hydroboration. It's still a summary. Only substrate control & pinene reagents. www.makingmolecules.com/blog/asymhyd...

No MakingMolecules #ChemEd summary today as NZ_Molecules is in Singapore with the wonderful folk at Gerstel (& only being a tiny bit jealous of their kit).

I feel a summary of sensory directed analysis coming at some point as it is simply fascinating (& a powerful technique to help at work).

A graphical summary of anti-Markovnikov addition to alkenes. It starts by showing the different products possible by hydrobromination and how the choice of reagent and control the regiochemistry. The second box contains the radical chain mechanism that explains anti-Markovnikov addition of HBr. The second half of the summary looks at hydroboration-oxidation and its mechanism.

A #ChemEd #Chemistry #ChemSky summary of anti-Markovnikov addition to alkenes using radical hydrobromination or hydroboration/oxidation. It's classic UG material introducing regioselectivity/stabilising intermediates. It's a simplification, more at www.makingmolecules.com/blog/antimar...

A summary of common electrophilic addition to alkenes including bromination, bromohydrin formation, hydration, epoxidation, hydrogenation, dihydroxylation, and radical reactions.

No new #ChemEd #Chemistry #ChemSky summary today, just an attempt to summarise the alkene chemistry that has been covered in the last couple of infographics. It also acts as a spoiler for next week's look at anti-Markovnikov addition.
Hopefully it still has some use.

A #ChemEd #Chemistry #ChemSky intro to the frontier molecular orbital view of electrophilic addition to alkenes. It is a companion to the last one (bsky.app/profile/maki...). It is an oversimplification but useful at #UG level (I hope).
It shows the limitations of curly arrow mechanisms.
Enjoy.

A summary of the reactions of alkenes behaving as nucleophiles. This covers the common examples such as the addition of HX, bromination, bromhydrin formation, epoxidation with peracids and syn dihydroxylation. In each case, I've given the curly arrow mechanism and a brief explanation of any regioselectivity. There is also a quick overview of carbocation stability (again, to help with the explanation of regioselectivity).

The 1st in a series of #ChemEd #Chemistry #ChemSky summaries on the reactions of alkenes. I'm starting with nucleophilic alkenes & the common UG reactions of the addition of HX, Br2, epoxidation etc. It's a bit crowded but hopefully it is useful. More details & reactions over the coming weeks.

A summary on nucleophilic acyl substitution. It starts with the loathsome chart of carboxylic acid derivative reactivity (with the addition of pKa just to highlight the important of leaving group on reactivity as well as the normal discussion of electrophilicity). Then there is the mechanism for the formation of acyl chlorides. Important for chemists, not so important for those interested in biology/biochemistry. Then there are three general mechanisms that can be applied to a host of reactions. The first is the attack of an anionic nucleophile. The second is acyl substitution with a neutral nucleophile and finally we have acid-catalysed acyl substitution. Hopefully these can be applied to the vasty majority of reactions that UG will encounter.

A #ChemEd #Chemistry #ChemSky summary of acyl substitution. There is one mechanism repeated multiple times (with variations). It is addition & elimination. Acylation is possibly the most important reaction (along with proton transfer) for non-chemists taking chemistry. Hope this is useful. Enjoy.

A summary of the condensation reactions of aldehydes/ketones. This is nucleophilic addition to the carbonyl with substitution of the oxygen atom. There are six sections. The first shows the formation of an acetal or addition of two equivalents of alcohol across an aldehyde or ketone. The second shows the reverse reaction, the addition of water across an acetal to give an aldehyde or ketone. The third box shows the mechanism of acetal formation and discusses how to make the reaction irreversible. The fourth section is imine formation and the addition of a primary amine to an aldehyde/ketone. It includes the mechanism. The fifth box is enamine formation by using a secondary amine. And finally there is summary about the differences between the addition of alcohols, primary or secondary amines.

More nucleophilic addition to aldehydes/ketones, this #ChemEd #Chemistry #ChemSky summary covers condensation & the formation/hydrolysis of acetals, imines & enamines. The mechanism is the same each time, but understanding why they deliver different products is important. Enjoy

A summary of the simple models for diastereoselective addition to aldehydes/ketones. The summary is divided into seven sections. 1. An introduction showing a nucleophile attacking an aldehyde with an α stereocenter. 2. An assumption that the nucleophile approaches along the Bürgi-Dunitz angle. 3. The nucleophile will be assumed to be a bare anion (this box shows that this is rarely true). 4. Felkin-Anh model. 5. Polar Felkin-Anh model. 6. Modified Cornforth model. 7. Cram chelation model.

A #ChemEd #Chemistry #ChemSky intro to models for explaining diastereoselectivity of nuc addition to C=O with an α stereocentre. It is a huge simplification. A tease for a fascinating subject. Other models exist but these are the ones often found at UG. Enjoy www.makingmolecules.com/blog/diaster...

Nucleophilic addition to aldehydes and ketones. This is an introduction to this vital reaction. It just covers simple addition and some guidelines to whether the reaction is reversible or irreversible. Hopefully, it acts as the foundations to more discussion about specific examples. There are 5 boxes. 1. Shows why the carbonyl group is electrophilic. 2. looks at the general reaction mechanism of addition and then protonation (and I am aware that this can be reversed but you've got to stat somewhere). 3. Is irreversible addition and protonation. 4. Is reversible addition with either a nitrile or alcohol. 5. Finally shows the orbitals but is really just a teaser.

This #ChemEd #Chemistry #ChemSky summary is an intro to nucleophilic addition to aldehydes/ketones. It's the 1st of many as I think carbonyl addition is far more useful than the traditional Sn1/Sn2 approach for teaching the basics (& more examples in biology). Hopefully it's useful. Enjoy.

Two slides from a science communication workshop given to MESA students. The first slide is the title and says "Tips on Science Communication" and "Gareth Rowlands" Second slide was a summary that covers the four key concepts: 1. Have one big idea, 2. Know your audience, 3. Present a story, 4. Refine, edit and practice.

Two more slides. The first shows pictures I made using PowerPoint - one is of a small extracellular vesicles and the other is of a membrane used in TRPS for counting particles. The second slide shows how you can use the three act model to introduce a story to the communication. It is based around the AND, BUT, THEREFORE method of story telling.

There haven’t been any updates to MakingMolecules, as I was preparing a workshop on #SciCommun for MESA www.linkedin.com/company/macd...
These slides (alt text for an explanation) give a flavour of the day.
It was a fun day with a great bunch of scientists.
MakingMolecules will return soon(ish).