1

I was reading about synthesis of alkyl halides from $\ce{PX3}$. I want to know the mechanism for this reaction. According to Solomons and Fryhle, no rearrangement takes place in case of $\ce{PBr3}$ , which leads me to think that the mechanism is SN2. But what about phosphorus bromides and iodides?

A Google search confirmed that the mechanism for reaction with phosphorus tribromide is indeed SN2, but I could not find anything on trichlorides and iodides. I need help for those.

Thanks.

Waylander
  • 22,035
  • 4
  • 37
  • 58
Anurag Baundwal
  • 382
  • 4
  • 20
  • 1
    Why do you think they may be different? – Waylander Apr 24 '18 at 11:59
  • HBr undergoes AMK addition to an alkene in the presence of peroxide whereas other hydrogen halides do not. I think that anything is possible in chemistry and I do not want to make a mistake if a tricky question based on this appears in my exam. – Anurag Baundwal Apr 24 '18 at 12:21
  • The HBr is quite different from the phosphorus halides as there is no protonation step on the alcohol – Waylander Apr 24 '18 at 14:15
  • https://chemistry.stackexchange.com/questions/69063/if-socl2-reacts-with-alcohols-via-sni-why-doesnt-pocl3 – Mithoron Apr 24 '18 at 15:25
  • Thanks for the links @Mithoron ! The reaction with $PCl_3$ looks like S_N^2 or S_N^i to me but I can't quite tell which. Which one is it? – Anurag Baundwal Apr 25 '18 at 09:03
  • I would assume that since the other answer suggests PCl3 gives the inverted product, it occurs via SN2. – Buck Thorn Sep 11 '23 at 15:36
  • see https://www.masterorganicchemistry.com/2015/03/20/pbr3-and-socl2/ (see step 4) – Buck Thorn Sep 11 '23 at 15:40

0 Answers0