Corey–Kim oxidation

The Corey-Kim oxidation or Corey-Kim reaction was first described in 1972 by the American chemist Elias James Corey and Choung Un Kim. The reaction is allowed to primary or secondary alcohols by the addition of gaseous chlorine (Cl2) and dimethyl sulfide to the corresponding aldehydes or ketones to oxidize. It is easy to use, highly selective and efficient. Corey -Kim oxidation, is related to the Dess-Martin oxidation, Swern oxidation and the Pfitzner - Moffatt oxidation.

Mechanism

First one is dimethyl sulfide (1) with chlorine (Cl2) to, whereby the salt ( 2). This is added to a primary or secondary alcohol, it is desired to oxidize. Can depart from the molecule and is itself a Dimethylalkoxyalkan 5: This molecule 4, which (HCl briefly) by rearrangement of electron pairs hydrogen chloride is formed. 5 and 6 are two resonance structures. This one is working with a base ( triethylamine here ), so a methyl group of the sulfur is deprotonated, thereby obtaining 7. Rearrangement of electron pairs, the dimethyl sulfide used to start splits off and forms the desired aldehyde (R1 = organic radical, R 2 = hydrogen atom) or the desired ketone (R1, R2 = organic radical ). The dimethyl thus functions only as a catalyst in this reaction.

Laboratory use instead of chlorine (Cl2) is often N-chlorosuccinimide (abbreviated to NCS ) was used as such the formation of hydrogen chloride can be prevented. In the industry but this is omitted for reasons of cost.