July 09, 2020, 07:44:22 PM
Forum Rules: Read This Before Posting


Topic: Synthesis of stannane compound  (Read 1553 times)

0 Members and 1 Guest are viewing this topic.

Offline rolnor

  • Chemist
  • Full Member
  • *
  • Posts: 992
  • Mole Snacks: +64/-5
Re: Synthesis of stannane compound
« Reply #15 on: December 17, 2019, 11:59:47 PM »
One good way to quench this time of sample is to mix it with a dropp of acetone, RF should go down if the lithiation is successfull.
after quenching with acetone, will  I see the spot of R-Li? If I don't quench, which kind of spot will I see? Because in this case, after lithiation I see a new spot with lower Rf to compare with starting material (5-octylthiophene)
If you quench with acetone, you get the tertiary alcohol from addition to the carbonyl in acetone, this product will be much more polar then the starting material. If you dont quench you will see the compound with a hydrogen instead of a bromo because the lithio-compound will be hydrolyzed on contact with moisture and silica on the tlc-plate. This compound will also be a little more polar then the startingmaterial.
I think you are doing everything right, its surprising it does not work.

Offline Hachiko

  • Regular Member
  • ***
  • Posts: 43
  • Mole Snacks: +0/-0
Re: Synthesis of stannane compound
« Reply #16 on: December 18, 2019, 02:09:47 AM »
One good way to quench this time of sample is to mix it with a dropp of acetone, RF should go down if the lithiation is successfull.
after quenching with acetone, will  I see the spot of R-Li? If I don't quench, which kind of spot will I see? Because in this case, after lithiation I see a new spot with lower Rf to compare with starting material (5-octylthiophene)
If you quench with acetone, you get the tertiary alcohol from addition to the carbonyl in acetone, this product will be much more polar then the starting material. If you dont quench you will see the compound with a hydrogen instead of a bromo because the lithio-compound will be hydrolyzed on contact with moisture and silica on the tlc-plate. This compound will also be a little more polar then the startingmaterial.
I think you are doing everything right, its surprising it does not work.
Thank you for your sharing.

Offline Hachiko

  • Regular Member
  • ***
  • Posts: 43
  • Mole Snacks: +0/-0
Re: Synthesis of stannane compound
« Reply #17 on: December 22, 2019, 07:58:24 PM »
Are there any methods for me to treat Bu3SnCl to reuse it?

Offline rolnor

  • Chemist
  • Full Member
  • *
  • Posts: 992
  • Mole Snacks: +64/-5
Re: Synthesis of stannane compound
« Reply #18 on: December 22, 2019, 11:22:05 PM »
Do you mean purify it? Distillation.

Offline Hachiko

  • Regular Member
  • ***
  • Posts: 43
  • Mole Snacks: +0/-0
Re: Synthesis of stannane compound
« Reply #19 on: December 23, 2019, 02:24:59 AM »
Do you mean purify it? Distillation.
Thank you!

Offline Hachiko

  • Regular Member
  • ***
  • Posts: 43
  • Mole Snacks: +0/-0
Re: Synthesis of stannane compound
« Reply #20 on: December 23, 2019, 02:32:22 AM »
Do you mean purify it? Distillation.
Distillation seems a little bit dangerous because it's toxic. Could I use the molecular sieve to remove water inside? Because I think the problem may come from the moisture.

Offline rolnor

  • Chemist
  • Full Member
  • *
  • Posts: 992
  • Mole Snacks: +64/-5
Re: Synthesis of stannane compound
« Reply #21 on: December 23, 2019, 06:08:17 AM »
No, if you get moisture it will react very fast, you get the tributyltinoxide.
« Last Edit: December 23, 2019, 06:38:21 AM by rolnor »

Offline Hachiko

  • Regular Member
  • ***
  • Posts: 43
  • Mole Snacks: +0/-0
Re: Synthesis of stannane compound
« Reply #22 on: December 23, 2019, 06:43:54 AM »
No, if you get moisture it will react very fast, you get the tributyltinoxide.
You means moisture will react with Bu3SnCl to form tributyltinoxide. So could it be the reason why Bu3SnCl doesn't work? I doubt that problem come from Bu3SnCl.

Offline kriggy

  • Chemist
  • Sr. Member
  • *
  • Posts: 1393
  • Mole Snacks: +117/-15
Re: Synthesis of stannane compound
« Reply #23 on: December 25, 2019, 02:13:29 PM »
I would check the purity of the stannane, NMR works fine for it. If your bottle is old, get a new one its not that expensive.
Im not sure exactly about your procedure but I would use different base because BuLi can react with tributyltinCl to form tetrabutyl tin. Try LDA or tBuLi.
Quench the organoLi with water before TLC to get the dehalogenated aryl (if you have TLC of that) you can also use DMF to get the aldehyde and stain it with DMP.
Also, the reaction might need some time and temperature, maybe warm it to room temperature after the addition is complete. The organotin reagents are super nonpolar, be sure to check with suitable mobile phases (we used pure hexanes for that).

Maybe check this procedure
http://orgsyn.org/demo.aspx?prep=CV8P0268


Offline rolnor

  • Chemist
  • Full Member
  • *
  • Posts: 992
  • Mole Snacks: +64/-5
Re: Synthesis of stannane compound
« Reply #24 on: December 25, 2019, 04:36:14 PM »
I would check the purity of the stannane, NMR works fine for it. If your bottle is old, get a new one its not that expensive.
Im not sure exactly about your procedure but I would use different base because BuLi can react with tributyltinCl to form tetrabutyl tin. Try LDA or tBuLi.
Quench the organoLi with water before TLC to get the dehalogenated aryl (if you have TLC of that) you can also use DMF to get the aldehyde and stain it with DMP.
Also, the reaction might need some time and temperature, maybe warm it to room temperature after the addition is complete. The organotin reagents are super nonpolar, be sure to check with suitable mobile phases (we used pure hexanes for that).

You can not use LDA if you want metal-halogen excange as in this case. N-BuLi works fine is my experience. You will get quench automaticaly if you put the lithiated material on a TLC-plate.

Maybe check this procedure
http://orgsyn.org/demo.aspx?prep=CV8P0268

Offline kriggy

  • Chemist
  • Sr. Member
  • *
  • Posts: 1393
  • Mole Snacks: +117/-15
Re: Synthesis of stannane compound
« Reply #25 on: December 26, 2019, 04:28:36 AM »
Yeah youre right, LDA doesnt exchange, I mixed that up with procedure we used (Bu3SnH + LDA then quench with electrophile)

Offline rolnor

  • Chemist
  • Full Member
  • *
  • Posts: 992
  • Mole Snacks: +64/-5
Re: Synthesis of stannane compound
« Reply #26 on: December 26, 2019, 03:52:37 PM »
Yea kriggy, thats an interesting reagent, Bu3SnLi, I have used it too. Its a "lithiated metal".

Offline Hachiko

  • Regular Member
  • ***
  • Posts: 43
  • Mole Snacks: +0/-0
Re: Synthesis of stannane compound
« Reply #27 on: December 27, 2019, 09:02:59 PM »
Thank you all for your valuable advice.

Sponsored Links