Comments on: The Lies We Tell

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

On The Synthesis Of Ketones « B.R.S.M. — Wed, 14 Sep 2011 22:37:42 +0000

[…] don't get told the whole truth as undergraduates, because most of us can't handle the truth (well, not all of it). I appreciate that trying to convey even the basic concepts of organic synthesis to a large room […]

By: James

James — Sun, 21 Aug 2011 21:28:45 +0000

In reply to James. 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).

By: BRSM

BRSM — Sun, 21 Aug 2011 21:16:56 +0000

In reply to James. 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).

By: James

James — Sat, 20 Aug 2011 11:56:23 +0000

In reply to BRSM.

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?

By: BRSM

BRSM — Fri, 19 Aug 2011 07:38:35 +0000

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.

By: James

James — Tue, 16 Aug 2011 02:23:55 +0000

In reply to Ray Putra Prajnamitra. 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.

By: Ray Putra Prajnamitra

Ray Putra Prajnamitra — Tue, 16 Aug 2011 01:59:42 +0000

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 =)

By: John Spevacek

John Spevacek — Wed, 10 Aug 2011 16:15:45 +0000

I like the closing statement. It will replace the other adage that I carried around: Chemistry is the science of progessive lying.

By: James

James — Wed, 10 Aug 2011 15:30:31 +0000

I know. Heresy!!! That’s why I’m writing this in August when nobody checks this blog.

By: azmanam

azmanam — Wed, 10 Aug 2011 15:18:15 +0000

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…”