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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: gabsanacu on February 15, 2021, 01:34:22 AM

Title: I need help with synthesis of compounds
Post by: gabsanacu on February 15, 2021, 01:34:22 AM

Instructions are: "Propose synthesis steps for each of the following examples. Write the reactants, catalysts and intermediates necessary to obtain the final product. It is not necessary to write the mechanisms of reactions."

I have no idea how to do two of those exsercises (Attached image).

Thank you so much in everything you can help me.

Title: Re: I need help with synthesis of compounds
Post by: gabsanacu on February 15, 2021, 01:41:55 AM

I could do this for the first one, but I don´t know what else to do. And the second I really don´t understand

Title: Re: I need help with synthesis of compounds
Post by: rolnor on February 15, 2021, 06:18:50 AM

I think d is not so easy, in e can you start with adding HBr to the alkene?

Title: Re: I need help with synthesis of compounds
Post by: kriggy on February 15, 2021, 08:13:39 AM

You probably want a different nucleophile but im not sure if you covered in the class (dunno about the level of this excercise)
hint: umpolung strategy seems like a way to go here

Title: Re: I need help with synthesis of compounds
Post by: rolnor on February 15, 2021, 12:53:00 PM

If you use umpolung like 1,3-dithiane you initially get a alkoxide together with the tertiary bromide, this could result in ring-closure or elimination, I dont like it. Maybe there is some clever chemistry that can solve this, I think its tricky. Maybe its possible to use trans-metalation to get a zinc-dithiane reagent that forms a less nucleophilic/basic alkoxide.