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By James Ashenhurst

The Lies We Tell

Last updated: September 12th, 2022 |

Zed Shaw teaches a course in writing Python called “Python the Hard Way“. Because the hard way is easier, he says.

In the end, he’s right. If you really want to learn organic chemistry, the hard way is easier. In graduate school I had to un-learn a lot of the half-truths I was taught in the introductory courses I took as a chemistry major and it still angers me somewhat that nobody thought to give me the straight dope. A lot of the reactions (and reagents, especially)  that are covered in a typical sophomore class bear faint resemblance to reactions you’d ever bother using if you became a professional organic chemist. Not only that, some of the concepts are half-truths too.

But half-truths are easier and faster to teach. The “easy way” to get across organic chemistry is to oversimplify things. I do it all the time. Every instructor does it to some extent. Something is true 98% of the time, so we lie and say it’s “always” true.

Look out for the words “always” and “never” – they’re the cloaks we use for our lies of omission.

1-platypus

Why tell these lies of omission? Because they save time. It can take a lot of time and effort to bother explaining all the exceptions to the rules, and for the purpose of the class, they’re not always crucially important. Time is limited. The attention of the class can be limited. And let’s be honest – the talent of the class can be limited too. With some students, you’re delighted if you can just get the basic concepts across.

Furthermore, many students don’t really want to learn organic chemistry per se.  What they want is a line on their transcript that states that they have taken a course in organic chemistry, and done acceptably well relative to the rest of the class. That’s just the way it is sometimes. I’m fine with that.

But it doesn’t mean that somewhere it can’t be said that – “we’re only giving you a part of the story here”, or “this explanation will have to do for now”. So you can think of this post as kind of a penance for all the lies I’ve helped to perpetuate in my short time as a freelance instructor.

So here are some of the most common lies I’ve told, and an attempt to impart more of the “whole truth”.

2-lieswetell

I can’t find it right now, but I am looking for a quote I read somewhere that said something like:

“Progress in teaching a course can be measured by the necessity of telling smaller and smaller lies. “

00 General Chemistry Review
01 Bonding, Structure, and Resonance
02 Acid Base Reactions
03 Alkanes and Nomenclature
04 Conformations and Cycloalkanes
05 A Primer On Organic Reactions
06 Free Radical Reactions
07 Stereochemistry and Chirality
08 Substitution Reactions
09 Elimination Reactions
10 Rearrangements
11 SN1/SN2/E1/E2 Decision
12 Alkene Reactions
13 Alkyne Reactions
14 Alcohols, Epoxides and Ethers
15 Organometallics
16 Spectroscopy
17 Dienes and MO Theory
18 Aromaticity
19 Reactions of Aromatic Molecules
20 Aldehydes and Ketones
21 Carboxylic Acid Derivatives
22 Enols and Enolates
23 Amines
24 Carbohydrates
25 Fun and Miscellaneous
26 Organic Chemistry Tips and Tricks
27 Case Studies of Successful O-Chem Students

Comments

Comment section

10 thoughts on “The Lies We Tell”

  1. Pingback: On The Synthesis Of Ketones « B.R.S.M.

  2. Did you ever see the 2007 rebuttal in JACS to the classic Nature paper on the ethane rotational barrier? After more calculations and lots of stuff I don’t understand the authors concluded the origin to be about 25% hyperconjugation and 75% sterics. I don’t know enough computational chemistry to comment on the validity of this conclusion. Some references and free commentary at http://comporgchem.com/blog/?p=37. I have a feeling a saw an even more recent paper on this, but I can’t find it at the moment.

    As a current PhD student I’m still trying to unlearn the lies of my undergraduate courses. A couple of weeks ago I saw DBU used in a Baylis Hillman reaction. There goes another one.

    Reply

    1. Thanks for the link. I’m no computational chemist either… but if one’s going to introduce hyperconjugation in the course, the rotational barrier of ethane seems as good a time as any to do so.

      I don’t understand – what was the ‘lie’ about the BH?

      Reply

      1. The ‘lie’ was that DBU is a non nucleophilic base, and doesn’t do things like add to unsaturated esters. I agree that ethane’s a good way to introduce the concept of hyperconjugation (well, that or cation stability as you say).

        Reply

      2. Ha! yeah, there’s really no such thing as a “non-nucleophilic base”, or even a “non-coordinating solvent”. There have been metal complexes isolated with CH2Cl2 as a ligand for example (among many others).

        Reply

  3. Thank you for “telling the truth” =)
    A friend of mine was doing Friedel-Craft alkylation to an aniline using AlCl3… He tried for months and failed miserably.. Now I can explain to him about the lie =)

    Reply

    1. It works OK, you just need to protect the amine as an amide. Then it will work. I would recommend your friend read the relevant section in March’s Advanced Organic Chemistry, this point and many others will become more clear.

      Reply

  6. many students don’t really want to learn organic chemistry per se.

    WHHAAAAAAAAAAAAATT????

    I like the phrases, “For our purposes…” or “To a first approximation…”

    Reply

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