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Cyclopropanation reactions of enones with lithiated sulfoximines: Application to the asymmetric synthesis of chiral cyclopropanes

Journal Article


Abstract


  • Stabilized lithiated sulfoximines 2 and 9 undergo highly diastereoselective Michael reactions with acyclic enones under kinetically controlled conditions. At rt the initially formed anionic Michael adducts undergo intramolecular displacement of the sulfonimidoyl group, with inversion of stereochemistry at the carbon bearing the nucleofuge, to give cyclopropanes. Lithiated sulfoximines derived from S-alkyl sulfoximines give mixtures of 1,2- and 1,4-adducts with enones mider kinetically controlled conditions. However, at rt the 1,2-adducts are in equilibrium with their corresponding 1,4-adducts. The 1,4-adducts are formed in a highly diastereoselective manner and are rapidly converted to diastereomerically pure cyclopropanes in good to excellent yields. Optically active versions of these sulfoximines give cyclopropanes in high enantiomeric purities.

Publication Date


  • 1997

Citation


  • Pyne, S. G., Dong, Z., Skelton, B. W., & White, A. H. (1997). Cyclopropanation reactions of enones with lithiated sulfoximines: Application to the asymmetric synthesis of chiral cyclopropanes. Journal of Organic Chemistry, 62(8), 2337-2343. doi:10.1021/jo962216i

Scopus Eid


  • 2-s2.0-0030989390

Web Of Science Accession Number


Start Page


  • 2337

End Page


  • 2343

Volume


  • 62

Issue


  • 8

Abstract


  • Stabilized lithiated sulfoximines 2 and 9 undergo highly diastereoselective Michael reactions with acyclic enones under kinetically controlled conditions. At rt the initially formed anionic Michael adducts undergo intramolecular displacement of the sulfonimidoyl group, with inversion of stereochemistry at the carbon bearing the nucleofuge, to give cyclopropanes. Lithiated sulfoximines derived from S-alkyl sulfoximines give mixtures of 1,2- and 1,4-adducts with enones mider kinetically controlled conditions. However, at rt the 1,2-adducts are in equilibrium with their corresponding 1,4-adducts. The 1,4-adducts are formed in a highly diastereoselective manner and are rapidly converted to diastereomerically pure cyclopropanes in good to excellent yields. Optically active versions of these sulfoximines give cyclopropanes in high enantiomeric purities.

Publication Date


  • 1997

Citation


  • Pyne, S. G., Dong, Z., Skelton, B. W., & White, A. H. (1997). Cyclopropanation reactions of enones with lithiated sulfoximines: Application to the asymmetric synthesis of chiral cyclopropanes. Journal of Organic Chemistry, 62(8), 2337-2343. doi:10.1021/jo962216i

Scopus Eid


  • 2-s2.0-0030989390

Web Of Science Accession Number


Start Page


  • 2337

End Page


  • 2343

Volume


  • 62

Issue


  • 8