[AlphaScent]

I am trying to figure the cheapest way to brominate 2-pentyn-1-ol. 

I first thought Finkelstein may be the way to go via the mesylate.  It is two steps though.

Then I thought triphenylphosphosphine and bromine, but it is costly.

Lastly, I thought about Phosphorus Tribromide.  Will this work easily for propargly alcohols??

Does anyone have any experience??

This is done neat, right?  With pyridine as an HBr scavenger???

[discodermolide]

Finkelstein needs low temp to avoid allene formation.
PBr₃ is probably the way to go.

Have not done either for a long time now

[AlphaScent]

I am not doing finkelstein.

I found a great procedure in a book by a chemist named Brandsma.  Has exactly what I need.

Done in ether with a bit of pyridine at -35.  Then bring to rt and reflux for 30 min.

Not bad.

[orgopete]

I cannot tell you whether this is good advice or not, but I'd look up your target compound. It looks simple enough that I assume it is known. (For kicks, I'd sometimes compare what they were paying me with the cost of trying a "new" route to a known compound. I didn't try too many new routes. It just wasn't worth it. That is also why I bought something if I could. Just sayin.)

[AlphaScent]

ORgopete,

I understand.  We are trying to make starting materials so it is cheaper.  On scale, it will be cheaper.

The PBr3 is the route to take here. 

[zsinger]

PBr3 SURELY!  As stated, you will get the allene with Finkelstein if the temp is not uber cold!  Too expensive to conduct, and 2 steps as you said.
      -Zack