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Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: Clarence426 on May 04, 2012, 09:50:15 AM

Title: Can sodium nitrite oxidize Phosphine??
Post by: Clarence426 on May 04, 2012, 09:50:15 AM
I have coupled the bis(2-cyanoethyl)-N, N-diisopropyl Phosphoramidite on a OH group of a sugar and form a phosphine containing sugar. May I know if i add sodium nitrite in the next step, will the phosphine convert to phosphine oxide or others?

Thanks
Title: Re: Can sodium nitrite oxidize Phosphine??
Post by: discodermolide on May 04, 2012, 10:52:34 AM
Quote from: Clarence426 on May 04, 2012, 09:50:15 AM
I have coupled the bis(2-cyanoethyl)-N, N-diisopropyl Phosphoramidite on a OH group of a sugar and form a phosphine containing sugar. May I know if i add sodium nitrite in the next step, will the phosphine convert to phosphine oxide or others?

Thanks


It may do, these things are very sensitive towards oxidants.
Title: Re: Can sodium nitrite oxidize Phosphine??
Post by: Clarence426 on May 05, 2012, 01:45:19 PM
Even at -10˚C at low pH?
Title: Re: Can sodium nitrite oxidize Phosphine??
Post by: discodermolide on May 05, 2012, 03:59:19 PM
Quote from: Clarence426 on May 05, 2012, 01:45:19 PM
Even at -10˚C at low pH?


It may do, these things are very sensitive towards oxidants.
Title: Re: Can sodium nitrite oxidize Phosphine??
Post by: Honclbrif on May 05, 2012, 04:52:09 PM
A quick search* isn't finding any strong evidence of oxidation of phosphines by nitrite, so such an oxidation may not occur. However, it may be that no one has tried it, or that they did and it wasn't what they wanted so they threw it away instead of reporting the results. Its pretty amazing how many seemingly simple reactions don't have very deep literature precedent.

Under mild conditions, tertiary amines don't generally react with HNO3 other than via simple Brønsted chemistry, but under the right conditions they will do some funky stuff. As Disco says, phosphines are very prone to oxidation so who knows what will happen.

My recommendations: either read up more on the problem, or say "damn the torpedoes" and go ahead with a small scale reaction if you've got the materials to try it out. Either on your target substrate or a similar but cheaper substrate and mix it up with nitrite and see if anything happens.

*really fast and really dirty