[Brook]

Does this proposed synthesis seem like it would follow through ok? Thanks in advance.

[discodermolide]

I don't see the first step happening as drawn. Hydrogenation under these conditions may well remove the chlorine as well.
If it doesn't how do you anticipate doing the ring closure?

[Dan]

In addition to what discodermolide has said:

- Look up the regioselectivity of radical bromination. Why do you expect to get the product you've drawn and not an isomer?
- Look up the regioselectivity of E2. Why do you expect to get the product you've drawn and not an isomer?
- Look up the mechanism of Diels-Alder reaction and cycloadditions in general. Diels-Alder is the reaction of an alkene with a diene - cycloaddition of two alkenes as you suggest does not give a 6-membered ring.

[mjpam]

I'm not sure the bromination and dehydrohoalogenation are needed to get to 1,4-dihydronaphthalene. There are at least one catalytic dehydrogenation and three electrophilic reductions that are stereoselective because they add syn to the multiple bond. I'm sure that they are compatible with alkyl halides, but they would be a good place to start looking, since they avoid having to re-create double bond after total hydrogenation of a triple bond that was in the desired place.

I'm not sure how to balance vagueness with specificity so that I have provided some information without giving away the answer. I apologize if my response too general to be helpful.