[discodermolide]

It is technically a reduction, i.e. the substitution of 2 hydrogens.

[joshphillips1977]

so number six is a substitution then?? Is it because the two H's take the place of the O?

[discodermolide]

The O is still there, the C=O had been substituted by the hydrogens.
HC=O to CH2OH.

[joshphillips1977]

Okay so it is an addition because the O is still there the only things that changed were the double bonded C=O and the addition of 2 H's right?

[discodermolide]

Yes.

[joshphillips1977]

Awesome!
Okay so #2 and #5 seem like they could be either elimination or Dehydration synthesis, the only difference is the Oxygen which does seem to be eliminated whereas in # two it appears to be just H that is being removed during the reaction...

[discodermolide]

2 would seem to be an elimination of H₂.
5 can be classified as an elimination of water or a de-hydration.

[joshphillips1977]

I have them as:
1. halogenation
2. Elimination
3. Substitution
4. Dehydration Synthesis
5. Dehydration
6. Addition

Am I close?

[discodermolide]

I think that's ok now.