#curly arrows

[idoscience]

Dess-Martin Oxidation

There's always some reactions that scientists wish they'd had the chance to do - this is one of mine. How freakin' awesome is that oxidising species!? How often do people get the chance to party with a hypervalent periodinane!? Exactly.  As a sexy alternative to the Swern oxidation, this reaction also converts primary alcohols into aldehydes (alkanals) or secondary alcohols into ketones (alkanones). This approach however, means no bad smells AND a room temperature reaction :)  That beautiful iodine complex encourages just a mild oxidation. This means no over-oxidising to make some unwanted carboxylic (alkanoic) acid. It's also easily separated from your product mixture too -everybody wins ^_^ NB. The -Ac is just an acetyl group

[idoscience]

The Swern Oxidation

This approach to oxidation allows primary alcohols to be turned into pretty little aldehydes (alkanals) ^_^ I could lie and say that it's a great reaction to do, but I'd rather save you the disappointment. It smells. The sulfur compounds reek and resultantly cling to you >.< All the textbooks claim that it's a rotting egg smell. It's so much more than that *shudders*  That said, it is quite a cheap and simple means of carrying out a pesky oxidation step :)  We use a mild base to deprotonate the methyl group because strong bases would more likely attack the sulfur and force the alkoxide to act as a leaving group. This means you're no further forward with your oxidation and smell terrible.  In summation, a fantastically yielding reaction and quick/effective - but if you can get a clueless little newbie to do it then you should! :P

[idoscience]

The Nef Reaction

So the first photo shows the curly arrow mechanism of how the Nef reaction proceeds. The reaction is considered a bit old school these days, but who doesn't love classic chemistry? Like nerdy vintage-ness :D  The purpose of the reaction is pretty simple: converting a mid-chain nitro group into a ketone (alkanone).

 We can use a relatively weak base when extracting the proton from that chiral centre at the start. By doing this, we make certain that any other functionality within the molecule isn't interacted with (hopefully).  It's the use of sulfuric acid (H2SO4) that has rendered this reaction kinda obsolete. The acid is capable of decomposing the final product of the reaction. Industries are constantly looking to minimise costs and that includes maximising yields - ergo photo 2. By using ozone (O3) yield is maximised at no major cost.