The Formation of Cyclopropane Derivatives Bearing 1,2-Dicarbonyl Groups through Tandem Michael–Favorskii-Type Reactions with(E)-β-Styrylselenonium Triflate
A novel tandem Michael–Favorskii-type reaction is described. Treatment of active methylene carbanions, prepared by the reaction of NaH and active methylene compounds, with (E)-β-styrylselenonium triflate in DMF at 70 °C for 3 h gave cyclopropane derivatives bearing 1,2-dicarbonyl groups in moderate to good yields. On the other hand, the carbanions derived from malonates reacted with the selenonium salt to afford 1,1-dicarbonylcyclopropane compounds in good yields. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)