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Please login to access the full content or check if you have access via20.2.12.1.1.3 Method 3: Acylation of Trimethylsilyl Acetate
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Beignet, J., Science of Synthesis, (2007) 20, 572.
The C-acylation of the dianions of carboxylic acids is a possible route to β-oxocarboxylic acids. However, this method is only applicable to α-branched carboxylic acids and is not suitable for the preparation of 3-oxoalkanoic acids unsubstituted at the 2-position.[6] The dianion of acetic acid forms aggregates in tetrahydrofuran and is only slightly soluble. The reaction of this dianion with acid chlorides under various conditions leads to the production of unidentified materials.[6] Alternatively, trimethylsilyl acetate 11 is used as a substitute for acetic acid (Scheme 5). Deprotonation with lithium diisopropylamide generates the monoanion that adds efficiently to acid chlorides.[24] The intermediate trimethylsilyl ester 12 is more acidic than trimethylsilyl acetate and the use of 2 equivalents of base is necessary to drive the reaction to completion. Desilylation under mild acidic conditions yields the corresponding carboxylic acid 13.
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References
[6] | Meeeeee, M. M.; Meeeeee, M. M.; Meeeeee M. M. M., Me.; Meeee, M. M., M. Mee. Meee., (8888) 88, 8888. |
[24] | Meeee, M. M.; Meeeee, M. M., Meeee. Meeeee., (8888) 88, 888. |
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- 8.Meeeee-Meee, (8888) 88/8e, 888.
- 8.Meeeee-Meee, (8888) 8/8e, 888.