Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: ivanakaj on March 03, 2014, 05:06:35 AM
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I am in need of a mechanism of the lithiation reaction with n-BuLi on any heterocycle (i need oxazole, but any will do). and the mechanism of the subsequent formylation of the lithium-azole with dimethylformamide.
I would be very thankfull for a step by step mechanism if there is anybody willing to write it. Have been searching for one, but can't find nowhere.
I
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Bu- removes the proton, then the anion formed attacks DMF. Over to you.
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Yes...i need the mechanism of the both reaction. Mechanism of the first reaction , of lithiation is one that follows thorough a complex that forms between the n-Buli and N on the oxazole and directs the Li to position 2 on the oxazole ring. Ok, but the mechanism of the reaction after the carbanion attack on the DMF and the formation of subsequent intermediate?
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So by forum rules no-one here is going to give you a written step-wise mechanism for any reaction, we can help you along but you have to put in the work.
Yes, the oxazole is deprotonated at C2. The N directing is helpful but its also the most acidic proton (K2CO3 is capable of deprotonating to a sufficient degree for a number of reactions to take place).
If the oxazol(ium?) then attacks the aldehyde of DMF, what will likely happen next?
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I worked out the entire step by step mechanism....thank you all for input....:)
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Note the formylation in this way always followed by acid hydrolysis.
Thus, the nucleophilic addition towards DMF forms only intermediate.