Functionally substituted vinyl carbanions, 44. Synthesis of odd-numbered 13-crown-4 derivatives possessing a functional group and their application inC-lithiation of acrylates
✍ Scribed by Jatzke, Harald ;Schmidt, Richard R.
- Book ID
- 102902295
- Publisher
- John Wiley and Sons
- Year
- 1991
- Tongue
- English
- Weight
- 515 KB
- Volume
- 1991
- Category
- Article
- ISSN
- 0947-3440
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✦ Synopsis
Abstract
The synthesis of symmetrically hydroxy‐substituted 13‐crown‐ 4 derivatives 2 and 3 is reported. To this end, diol 7 is first deprotonated with potassium tert‐butoxide and then treated with ditosylate 6 in the presence of lithium perchlorate as a template. Base‐catalyzed addition of 2 and 3 to methyl propiolate affords β‐alkoxy‐substituted acrylates 1a and 1b, respectively. Treatment of 1a with LDA in THF generates the β‐C‐lithiated species 1a‐A as indicated by quenching with CH~3~OD and reaction with propanal; thus, β‐deutero derivative 1a‐(β‐D) and tetronate 4a, respectively, are obtained. Competition experiments between 1a and methyl β‐methoxyacrylate (1c) with LDA in THF exhibit for 1a a higher thermodynamic but practically the same kinetic acidity.