Hello,
For a schoolproject, I have to synthesize 5-methyl-3-hexen-2-one (see picture, 4). To synthesize this chemical I wanted to use an Aldol addition reaction with acetone (1) and isobutyraldehyde (2) and after that condensate (Aldol condensation) the intermediate (3).
In school I have learned the best way to do synthesize the intermediate is with LDA (litium diisopropylamide). This way you get a directed Aldol reaction. Firstly I would make a litium enolate of acetone and add isobutylaldehyde to form the intermediate.
However, after looking down the internet I couldn't find an article which describes a reaction with LDA in this way. I could only find articles which uses NaOH (for example: Tanaka, K.; Kobayashi, T.; Mori, H.; Katsumura, S. J. Org. Chem. 2004, 69, 5906−5925.). This article describes a 49% yield of 5-methyl-3-hexen-2-one (step 1 (Aldol addition) 69%, step 2 (Aldol condensation) 71%).
I was wondering if you think using LDA would make a greater yield? I think it would because less by-products would be synthesized in step 1 but I can't find any evidence online. I have checked other starting products and products if I could find evidence there but also without any results. I have to admit that I'm still in school and my searching skills might not be good.
I hope you can help me.
Kind regards,
Bjorn
P.S. I am sorry if my English is not perfect. English is my second language and I am not the best in it...