Comments on: Wedge And Dash Convention For Tetrahedral Carbon

By: James Ashenhurst

James Ashenhurst — Tue, 16 Apr 2024 19:19:06 +0000

In reply to Apurva. Wow, I messed up. Thank you so much for bringing this to my attention. Fixed!

By: Apurva

Apurva — Mon, 15 Apr 2024 12:00:57 +0000

The configurations under point 2 are same but those under point 3 are not same; they are mirror images of each other, i. e., enantiomers.

By: James

James — Tue, 22 Nov 2016 16:42:59 +0000

In reply to shivang. No, rotation never changes configuration. If you turn a car 90 degrees do the passengers end up in different seats or do the tires get transferred between sides? Of course not, right? It's the same thing.

By: shivang

shivang — Tue, 15 Nov 2016 14:13:16 +0000

does rotating by 90 degree change the configuration of molecule??

By: james

james — Thu, 14 Mar 2013 12:54:30 +0000

In reply to mevans. There is an art class component to it. Any time you draw a 3 dimensional object (whether it be a car, a table, or a molecule) there is always a choice made as to the perspective it will be drawn from. I try to keep hammering away at students to think of molecules as being no different from other 3 dimensional objects. Bridged compounds are a perfect example of molecules that freak students out the first time they see them drawn from the "side" perspective.

By: DrFreddy

DrFreddy — Wed, 13 Mar 2013 20:33:42 +0000

Splendid write-up!

If you think stereochemistry is difficult (so do I!), I wholeheartedly recommend taking a course in heterocyclic chemistry instead. Preferably one that is focused on unsaturated (aromatic) rings. 100 % free of wedges, iron-clad guarantee.

By: mevans

mevans — Wed, 13 Mar 2013 12:45:42 +0000

If I had a nickel for every time I saw a student draw “wedge and dash on opposite sides of the in-plane bonds” (Common Pitfall #1), I’d be loaded. It’s an extremely common, and extremely annoying, mistake. In my experience, it shows up most in bridged compounds where the bridgeheads are stereocenters.

This, in my experience, is one of those things that students don’t pay enough attention to. I suppose the trick is to convince them that organic chemistry is part science class, part art class.