Tuesday, January 19, 2010

Sonogashira Coupling

he reaction was first reported by Kenkichi Sonogashira and Nobue Hagihara in 1975.

The coupling of terminal alkynes with aryl or vinyl halides is performed with a palladium catalyst, a copper(I) cocatalyst, and an amine base. Typically, the reaction requires anhydrous and anaerobic conditions, but newer procedures have been developed where these restrictions are not important.


solvent/base : tea or other amine, DMF, MeCN
Pd (0) is needed, pd(pph3)4, also pd (II) can be used which will be reduced to pd (0) by alkyne. pdcl2(pph3)2.
CuI.
some additive can increase the rate and yields: ex. Bu4NI,
temp: rt or heat.

note:
1. electron deficient aromatic halides gave better yields. electron rich aromatics don't react well.

2 comments:

https://www.med-chemist.com said...

when one uses tetrakis and quarternary ammonium salts (as catalyst), one need to maintain anhydrous condition na ?

Weiwei TIAN said...

Yes, I think so.
the ammonium salts are used to activate the Cu alkyne species as I can remember.