[chloe126]

Hi everyone....I know this will probably come off as crappy that I'm asking for homework help but I really struggle in chemistry and the more ways that someone can explain a problem to me the better. The attached file is a set of practice homework problems for my upcoming exam. Any help with synthesis explanations would be greatly appreciated. Also any tricks that you use to remember reactions as well. I have horrible test anxiety with orgo and it seems that everything flies out of my head when I start writing the exam.

Also number four....I believe I have come up with a proper synthesis, but am unsure whether or not my prof forgot to make the substituent a Hydrogen rather than the methyl that it appears to be. What do you think???

Anyway...like I said, any help would be truly appreciated, thank you for your time in advance

[opsomath]

Homework questions are allowed but you will get more help the more specific questions you ask and the more of your own work you show.

Good question about 4, I see what you mean; you could make that in one step (or two depending on how you count em) if the methyl were a hydrogen. I don't think that's what's meant in the problem, though, since everything else will take a couple more steps.

I would think about ways you could install both of those groups. My thought is you can put them both on the same way. How do you take a carbonyl compound like your starting material, and put a new carbon-carbon bond going to its carbon?

You can always ask your professor, but that's my guess.

[chloe126]

Ok...so question then, if you believe it is supposed to be a methyl group, how would I add it?? should I add a hydroxyl so that the Hydrogen on the carbon with oxygen is removed, forming a double bond and then add to that? Or is it possible to use a Gringard reagent such as a benzene ring with MgBr as a substituent and then another Gringard like Ch3MgBr at the same time??

[nox]

For Q4 it's fine the way it is.

Just remember that you can always interconvert between a hydroxyl and a carbonyl group via redox chemistry, and adding a methyl group is no different than adding a phenyl group.

[chloe126]

For Q4 it's fine the way it is.

Just remember that you can always interconvert between a hydroxyl and a carbonyl group via redox chemistry, and adding a methyl group is no different than adding a phenyl group.

so then would I add it using a Gringard?? is that possible to do since the Oxygen will not have a double bond after I add the phenyl group?? or do I use the two Gringards at the same time??

[nox]

Well, there are ways of turning a hydroxyl group into a carbonyl group...

[voidSetup]

Could 4 not be done in one step with a secondary Grignard reagent?

[Honclbrif]

Secondary Grignard wouldn't work. As long as the carbon the alcohol is attached to originated as the aldehyde carbon, you've got to swap the proton for a methyl.

[orgopete]

Isn't number one (aldehyde to ketone) a clue as to how to do number four (aldehyde to ketone to tertiary alcohol)?

[james_a]

For synthesis I'd suggest starting with a list. Ask yourself: How is the product different from the starting material? What's new? What bonds have been broken and formed?

In the first example, for instance, "what's new" is that there are two extra carbons adjacent to the carbonyl and the H is gone. So you've formed a C-C bond and broken a C-H bond.
This is your "to do" list. Only look for reactions that will achieve one of the goals on your "to-do" list. This will make the search for reactions considerably easier.