[OC pro]

Did 75% of my Ph.D. on steroid partial synthesis and do know the old literature pretty well but that one is tricky.
Somehow in starting material B the position of the methyl group is illegitimate. Bromo and methyl have to be interchanged.

For the six-membered ring I would follow disco´s way. 2-Step reduction of the naphthol to the corrsponding tetralone, then Robinson Annulation using but-4-en-2-one will give the A, B and C rings (all six-membered). But for the five-membered ring I have no clue so far.

[discodermolide]

Did 75% of my Ph.D. on steroid partial synthesis and do know the old literature pretty well but that one is tricky.
Somehow in starting material B the position of the methyl group is illegitimate. Bromo and methyl have to be interchanged.

For the six-membered ring I would follow disco´s way. 2-Step reduction of the naphthol to the corrsponding tetralone, then Robinson Annulation using but-4-en-2-one will give the A, B and C rings (all six-membered). But for the five-membered ring I have no clue so far.

Would it be worth using the tetralone to construct Dane's diene? Then use the interchanged bromine and methyl in my scheme to make the A ring? See the following http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2852147/
by the way my diene should have a methyl ether.

[OC pro]

Diels-Alder approach is of course very elegant. Woodward used it in his syntheses of cortisone and cholesterol.

But, as mentioned in the post from bunsenburning Robinson Annulation has to be used!!

[orgopete]

I think the burningbunsen problem may have an error. I just don't see how the bromine is being used.

[discodermolide]

I think the burningbunsen problem may have an error. I just don't see how the bromine is being used.

I think you may be correct.

[OC pro]

I think the burningbunsen problem may have an error. I just don't see how the bromine is being used.

I was on the same track.

[OC pro]

Went through SciFinder and Reaxys. Starting naphthalene has never been described.
Looked also through ~20 syntheses of androstenedione A.

@ bunsenburning: From where do you have this?