Ketone to alkene regiochemistry What are the reagents for the following reactions:



Typically, when thinking about ketone to alkene reactions, one thinks of the Wittig reaction. However, I don't see an appropriate form of that reaction here. This was posed as a question on my problem sheet and I suspect - after having given it some thought - that it's just a Hoffman/Saytzev question.

For reaction A, I think reaction with $\ce{MeMgBr}$ to make the tertiary alcohol. At this point, one has to think of a way to get the least thermodynamically stable product (the kinetic product). Perhaps sulfuric acid? It would protonate the hydroxyl so the transition state wouldn't have significant alkene character and the "base" is bulky. Correct?

For reaction B, I think it should be reacted with $\ce{NaBH4}$ to make the secondary alcohol then elimination can be performed using whatever. Maybe sulfuric acid again or just tosylate it then use $^t\ce{BuOK}$. Does this sound right?
Part (a)

I agree with the previous comments that a Wittig reaction is the best way forwards especially in terms of regioselectivity of the double bond. PPh3, MeI and NaH would be an excellent combination. Perhaps draw the mechanism and you'll see how/why this work so well?

If you are interested, you could use (Cp)2Ti=CH2 also known as Tebbe's Reagent. Klaus Warzecha mentioned this already (above).

Part (b)

I like your idea of reducing, tosylating and using the non-nucleophilic base tBuOK