[AlphaScent]

In the following scheme you react a vicinal diol with methanesulfonyl chloride to get a mesyl chloride leaving group on only one of the hydroxyl groups. 

One of the hydroxyls is secondary and the other is tertiary.  Does then MsCl not react with the tertiary simply due to sterics or is there something I am not seeing? 

[discodermolide]

I think this is probably steric. You have to be careful with mesylates, especially with the choice of base. I have often experienced that the chloride ion of the amine base displaces the mesylate and you end up with a halide!

[AlphaScent]

That is great to keep in mind.  I should say this is all theoretical to me.  These are from past homeworks in a class I am to take this semester.  Just trying to get ahead.  I am realizing that I need help with my theory.

This is the next step in the synthetic scheme.  I have to think about this some more, but how is a 5 membered ring more energetically favorable than a 6? 

[kriggy]

From what I know  saturated 5 membered are more stable than saturated 6 membered and unsaturated 6 membered are more stable than unsaturated 5 membered because of ring strain.

[orgopete]

This probably has another name, but it reminds me of a benzylic acid rearrangement. I don't see ring size as a factor.