1-Lithio-2,2-diphenoxy-1-(phenylsulfonyl)cyclopropane as β-lithio acrylate and cyclopropanone acetal anion synthons

Article abstract of DOI:10.1016/S0040-4020(01)80161-7

1-Lithio-2,2-diphenoxy-1-(phenylsulfonyl)cyclopropane (4) reacted with alkyl halides to give the alkylated cyclopropyl sulfones 6, which were subjected to hydrolysis with TiCl₄ in CH₂Cl₂ followed by elimination of the phenylsulfonyl group with DBU to afford α,β-unsaturated esters 8 and small amount of β,γ-unsaturated esters 9. Furthermore, reductive removal of the phenylsulfonyl group of compound 6 by using 6% Na-Hg furnished 2-alkyl substituted cyclopropanone acetals 12 in good yields.