PBr3 and SoCl2

[Deepa100]

---

Members don't see this ad.

Hi,
Does anyone remember why SN2 works better for reactions of alcohols with HBr when you use PBr3 or SoCl2? I used to know...

 

[the lost crow]

The reaction isn't an SN2. It's Sn2-like in terms of stereochemistry. Losing an OH is unstable thus you have to enhance the leaving group.

 

[161927]

HBr is acidic, so if water leaves, carbocation rearrangements can occur. You may end up with the wrong product.

No rearrangements are possible with PBr3 and SOCl2 because they are SN2-like.

 

[Deepa100]

HBr is acidic, so if water leaves, carbocation rearrangements can occur. You may end up with the wrong product.

No rearrangements are possible with PBr3 and SOCl2 because they are SN2-like.

Got it, thanks.