Hey guys, I could really use your help. I have devised this wonderful novel route that gives desired in much fewer steps than before – with a small caveat. The final compound has a tin too many. As I cannot show you exact structures, this image will have to suffice. R is actually lots of things, such as fused ring and so forth.
Lithiation followed by water or acid is out of the question, because of other labile groups. I spent some time in both SciFinder and Reaxys, and much to my surprise, I could not find a catalytic system that does what I want. Can this really be? I mean, I bet that if I would want to to use this material in a Stille coupling, at least 10 % of the protodestannylated product (which in our case is desired) would be one of the byproducts. I am surprised no one has figured out a way to do this catalytically – or my skills with our precious search tools are not what they once were. You tell me!
For aliphatic stannanes, I found this recipe in which you take your material in methanol and add TMSCl. Super-dry HCl thus forms in situ, and protodestannylates the product. But sp3 is not sp2.
If you happen to sit on a magic method or literature reference, the comment field is wide open! Thank you.
Aryl stannanes can be protodestannylated with H-X, but with your pyridine nitrogen present, it may not be as easy as it looks. Easy to try, though. If that doesn’t work, your mention of the Stille coupling is a good lead. You would need H-Pd-X, which would cause transmetalation to give Bu3Sn-X and Ar-Pd-H, which would reductively eliminate. So, what are the ways (especially catalytically) to generate HPdX on purpose?
Nice lead(s). Look for instance for protodeborylation recipes — right to it. Thanks!
Pd(0), bulky phosphine ligand, and a stoichiometric acid chloride. Oxidative addition, b-hydride elimination to PdHX, transmetallation, reductive elimination.
e.g. https://pubs.acs.org/doi/abs/10.1021/ja9108424
Yes, yes, yes!
I guess Pd(0) and R3SnH would generate a Pd-hydride complex, right? So what’s next? Would an excess of that specie transmetalate with your pyridylstannane and ultimately generate your desired compound and a Sn-Sn compound? Maybe there are other hydride sources that might be more favourable? I do like question marks, I must say.
/FL
Oops, didn’t mean to publish my full name, drfreddy could you please edit?
Certainly.
Thanks.
I wonder if aryl stannanes would come off with a protic fluoride source like aq. 40% HF + acetonitrile (or NEt3.3HF) – tributylstannyl has very high affinity to fluoride, KHF2 is commonly used in organotin workup.
Also, if your molecule allows it, maybe you can just take a small sample and heat it to boil with Pd-C in water, to see what happens
I really blog also and I’m composing something similar to this specific posting,
“Help me delete this tin | Synthetic Remarks”.
Will you care in cases where I reallyimplement several of your points?
Thanks for your effort ,Elijah
Did you ever find a method to do this?
I recently had a ArSnBu3 compound left in MeCN/H2O for a few weeks at r.t. and it converted completely to what looks like the ArH (as judged by HPLC)