Recently one of my relatives have fallen ill and was prescribed with some colchicine. Looking at the structure of the molecule, and with nothing much to do, I decided to put my retrosynthetic skills to the test. Here is a picture of my thought process: enter image description here

Is there a better way to design a synthesis for this compound using the disconnection method.

From 11b, a Birch reduction is carried out to give the qunione 10b. A rearrangement of the ketone with methanediazonium gives 9b. A dihydroxylation with a peroxy acid and subsequent addition of water gives 8b. A double dehydration reaction with sulfuric acid, coupled with the protection of the ketone with propan-1,3-diol gives the seven-membered quinone 7b. A Heck reaction (or Ullmann reaction) with 7a with a palladium catalyst yields 6. (The protection group is thereafter labelled "PG") Friedel-Crafts acylation with ethanoyl chloride yields 5 (although on second thoughts, I should have done the acylation from 7a from the start). A Michael addition is then carried out with $\ce{BuLi}$ to lithiate the ketone to give the terminal imine 4. Since this terminal imine is unstable, a mild reducing agent converts the imine to the amine 3. The ketone is then removed by addition of dithiol and subsequently reduced by Raney nickel to form 2. Finally, a simple condensation reaction between the amine and acetic anhydride, followed by deprotection of the ketone using an acid, yields the final product colchicine, 1.

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    $\begingroup$ While this is an interesting question I have to agree that it is too broad. Maybe focus on a specific aspect of the synthesis or head over to the chat to discuss your question in more detail. $\endgroup$
    – bon
    Feb 1 '17 at 8:26

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