EntitledMillennial - 4-8-2016 at 14:14
Hello All,
First post here. A lot of people on here with a lot of experience.
As some of you may know Grubs II removal is difficult. Even after a normal phase flash chromatography I am left with a discolored product. I have read
several references for removal. Using basic cysteine, hydrogen peroxide, Lead acetate, the very expensive water soluble phosphine ligand(to
expensive). all of which are great however, my substrate contains an unsaturated 6 membered lactone which could be a Michael acceptor to any of these
doners(I know the phosphine isn't one)
1) does anyone have input or Grubs II removal?
ziqquratu - 4-8-2016 at 15:22
I've seen a co-worker use the hydrogen peroxide technique (the method described in http://www.sciencedirect.com/science/article/pii/S0040403909...) in the presence of a fairly reactive a,b-unsaturated lactam without noting any
oxidation of the substrate. I've also used that method extensively for cleaning up post-metathesis (albeit never on that particular type of system)
and it's really quite effective - although you still have to take care in your chromatography, because there's definitely something in there that's
difficult to fully remove!
EntitledMillennial - 4-8-2016 at 16:59
I'll check out the reference thanks.The product is a a much lower spot and often elutes with what I am assuming are the carbene portion of grubs II.
Thankfully the product is a solid and I should just recryst it after chromatography.
DJF90 - 8-8-2016 at 03:59
There was a recent OPRD paper where they detail scalable methods for removal of ruthenium after metathesis reactions. Perhaps it would be of use to
you.
http://pubs.acs.org/doi/abs/10.1021/acs.oprd.6b00138 (Free access via ACS AuthorChoice)