An efficient and highly stereoselective synthesis of cis-1-acetyl-2-aryl-6,6-dimethyl-5,7-dioxo-spiro-[2,5]-4,8-octadiones and beta,gamma-trans-beta-acetyl-gamma-aryl-butyrolactones

摘要

Acetylmethyltriphenylarsonium bromide 6 in the presence of potassium carbonate and trace water reacted with 2,2-dimethyl-1,3-dioxa-5-substituted-benzylidene-4,6-dione 2 at room temperature to give cyclopropane derivatives cis-1-acetyl-2-aryl-6,6-dimethyl-5,7-dioxo-spiro-[2,5]-4,8-octadiones 7 (X=p-CH3, p-Cl, H, p-NO2) or beta,gamma -trans-beta -acetyl-gamma -aryl-gamma -butyrolactones 8 (X=p-CH3O, p-N(CH3)(2), 3',4'-OCH2O-) with good yield and high stereoselectivity. [References: 8]