Will this simple reaction work?

[joelhunter1234]

Do you think this will work?

 

 

 

Solvent choice: Di-ethyl ether (nonreactive toward starting materials, has enough non-polar character to dissolve both starting materials) – I was thinking of using hexane, but because of the C=O polar bond in the dienophile I'm not sure that I would be a good solvent.

 

Catalyst choice: AlCl3 – Lewis acid catalyst – should coordinate with oxygen on the dienophile and increase reaction rate.

 

Workup reagent: Water - should wash lewis acid catalyst into aqueous layer. (H20+AlCl3 → Al(OH3) + HCL

 

Optimal conditions - Lower temperatures prevent polymerization of the diene, but would result in slow rate of reaction. The virtual lab program suggests 35 degrees gives the best yield but other Diels Alder syntheses I've looked at all seem to use high temperatures 100-200 degrees. ???

 

By-products : Aside from products from the polymerization of the diene, the only other products in the organic layer should be the unreacted starting materials ???

 

Method – to get 0.01 moles of product

 

Oven dry 100ml round bottom flask with stir bar, seal and allow to cool to room temperature.

Add 0.5g of anhydrous AlCl3 and reseal immediately.

Add di-ethyl ether solvent – 30ml.

Place flask in water bath @ 35 degrees with thermometer

Add 0.54g of diene and stir for a few minutes

Add 21g of dienophile (20:1 ratio dienophile:diene – this should favour the product I want?)

Let mixture stir at 35 degrees for 90 minutes

Pour reaction mixture into seperating funnel, add water.

Remove the aqueous layer (which should be the bottom since di-ehtylether has a density of 0.71g/ml)

Dry the organic phase with anydrous MgSO4

Filter into a small 50ml round bottom flask

Remove the remaining diethyl ether solvent using rot evap.

 

I'm not sure how to purify the product yet because I haven't been able to find solubility/b.p./ other data for the product.

 

By the way, does anyone know the name of the product lol?

[Zellinger]

I believe the name of the product would be 1,4-naphtoquinone.

 

Edit: you would have to add tetrahydro- in the name to indicate that two double bonds are missing.

[joelhunter1234]

Yea it's 4a,5,8,8a-tetrahydronaphthalene-1,4-dione synthesis I believe,

 

But have I got my solvent and catalyst choices correct?

[John Cuthber]

You might get an anthraquinone like by product from 2 dienes and a quinone but with a 20:1 ratio of quinone to butadiene there won't be muc..

The rest of it looks reasonable to me but it's not really my field.