# Mechanism for the formation of an alkyl halide from alcohol and phosphorus trihalide [duplicate]

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.

## marked as duplicate by Mithoron, Gaurang Tandon, Todd Minehardt, airhuff, M.A.R.Apr 25 '18 at 19:52

• 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 B. Apr 25 '18 at 9:03