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Does anyone know if it is possible to open an epoxide and do a 2-C extension using an enolate ion, say, of acetone? Here's an example of what I mean:

enter image description here

Based on what I know of enolate chemistry, this shouldn't be problematic, but I've never seen it.

I have done some preliminary literature searching and checked out masterorganicchemistry.com, etc. but have not been able to find anything about this.

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Never say never! :-) Here is the answer for your question (Ref.1):

Abstract: We report here that (1) enolate anions of five- to seven-membered cycloalkanones nucleophilically open cyclopentene and cyclohexene oxides in 57−76% yields and with 4−8:1 diastereoselectivity; (2) enolate anions formed regiospecifically via kinetic deprotonation of 2-cyclohexenone and 2-cycloheptenone open cyclohexene oxide in 60−62% yields and with 32−95:1 diastereoselectivity; and (3) an aryl methyl ketone enolate anion opens a monosubstituted epoxide as the key step in a short synthesis of the $\gamma$-hydroxyketone (GHK) aglycon of the natural product curculigine.

Graphical Abstract:

Epoxide Opening by Enolates

The product(s) and selectivity are depicted in following scheme:

Epoxide Opening

Reference:

  1. G. H. Posner, J. P. Maxwell†, M. Kahraman, "Mild, Fast, and Stereoselective Epoxide Opening by Ketone Enolate Anions. Application to Synthesis of the Norlignan Curculigine," J. Org. Chem. 2003, 68(8), 3049–3054 (DOI: 10.1021/jo020744q).
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