Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: student2012 on May 04, 2012, 05:30:54 PM
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I am currently taking an Organic Chemistry course online. I have a handle on the majority of information in the course, but have a really hard time when it comes to questions of how would you synthesis molecule A from molecule B, when it includes multiple steps. Does anyone have suggestions on how to approach these types of questions?
The one i'm currently looking at asks to: Outline the synthesis for each of the transitions shown. It shows Cycloheptanone to 2-methylcyclohexanone.
Thanks
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I … have a really hard time when it comes to questions of how would you synthesis molecule A from molecule B, when it includes multiple steps.
The one i'm currently looking at asks to: Outline the synthesis for each of the transitions shown. It shows Cycloheptanone to 2-methylcyclohexanone.
Join the club. Usually, problems are organized to practice reactions being discussed. So, the expected route should follow in context of the course. Secondly, I am of the opinion that working backwards as this problem requires, means you have to know the forward reactions very well. If you have difficulty drawing the product of a reaction if given the reactants, then it will be much harder to draw a starting material if only given the product.
This is not a trivial conversion. The greater the number of steps that may be involved, the greater the number of different alternatives that are plausible. Perhaps it would be useful to suggest something like, how can this transformation be carried out using an aldol (or similar) or photochemical route? Better still would be an attempt to show something plausible using relevant reactions.
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Just like solving math questions, in my opinion, practicing more question is the best way to get better at these type of question.
I don't really understand this synthesis, so I can't help you with this one. Sorry.
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I am currently taking an Organic Chemistry course online. I have a handle on the majority of information in the course, but have a really hard time when it comes to questions of how would you synthesis molecule A from molecule B, when it includes multiple steps. Does anyone have suggestions on how to approach these types of questions?
The one i'm currently looking at asks to: Outline the synthesis for each of the transitions shown. It shows Cycloheptanone to 2-methylcyclohexanone.
Thanks
This looks like a multiple step conversion. Maybe start with a Favosrkii rearrangement and see where we can go from there?
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This looks like a multiple step conversion. Maybe start with a Favosrkii rearrangement and see where we can go from there?
I think that is the wrong cyclopropanol. You need a bicyclo[4.1.0]heptan-1-ol or a different route.
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This looks like a multiple step conversion. Maybe start with a Favosrkii rearrangement and see where we can go from there?
I think that is the wrong cyclopropanol. You need a bicyclo[4.1.0]heptan-1-ol or a different route.
Sorry I don't follow! where does the cyclopropanol come in?
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Is this the reaction you were thinking of? I thought you would need the one shown below it.
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Is this the reaction you were thinking of? I thought you would need the one shown below it.
I was thinking of the top reaction, then doing a ketone to ketone conversion (dehomologation) then install the methyl group.
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The approach i took was from cycloheptanone was; reduce the ketone to an alcohol then dehydrate to cycloheptene. This is the part that i don't know if it is right: break the alkene and open the ring using KMnO4 which gives a 1,7-heptanedioic acid. Then an esterification using ethanol and acid catalyst (HCL), giving a 1-7 diester, allowing a intramolecular claisen condensation, followed by the alkylation of the methyl group. I end with the 2-methylcyclohexanone.
Not sure if thats correct, but its what i've come up with.
Can anyone double check this?
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Yes, I was going to suggest that as well, though I'm not sure what you mean by "alkylation of the methyl group". After the Dieckmann cyclisation you need to methylate the beta-ketoester and then decarboxylate.