[superg]

hi,

i got a question about palladium-catalysed reaction work-up(sonogashira coupling most of the time...). my main problem is the removal of black palladium, wihch is soluble in some polar solvents. it cause some problem if i use those solvents for column chromatography...

does anubody have some trick(s) for the Pd removal?

thx

[agrobert]

Dissolve your crude in less polar solvent and filter through a pad of celite.  Or run a short silica column (plug) before your purification column.

[russellm72]

Normally I have not come across such a problem but there are ways to lower your palladium content.

(a) Try using one of the palladium scavenging resins which are available from Biotage. I use this company a lot and genrally the resins are of good quality. I have however not used this particular resin.

(b) Try using encapsulated palladium and the derivatives.

http://www.reaxa.com/products/encapsulated-palladium-ii-catalysts.html

Never tried them but always been interested.

Of course it all depends on your budget......

Regards

R.