What is the problem with forming 2,3-dimethylcyclohex-2-en-1-one?


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> [![enter image description here](https://i.stack.imgur.com/mP3fb.jpg)](https://i.stack.imgur.com/mP3fb.jpg)
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I have suggested a mechanism for the formation of 3-ethyl-2-methylcyclohex-2-en-1-one **A** 


[![enter image description here](https://i.stack.imgur.com/LDpd5.jpg)](https://i.stack.imgur.com/LDpd5.jpg)


but the question says problems would be encountered if a similar route was used to make 2,3-dimethylcyclohex-2-en-1-one **B**. I think perhaps a decarboxylation step is involved? Can someone please explain how to get to **B** and the difficulties in the mechanism?




Your starting product for A is symmetrical, but your starting product for B will be asymmetrical - one carbon less on one side. This is going to mean you may get 2 or more different products; B may not be your major product, and you'll have to separate them afterwards. I don't believe there's inherently a tricky difficultly in the mechanism for B.


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