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 β,γ-Trans-β-Acetyl-γ-Aryl-Butyrolactones

Abstract

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

Key Words:

• Stereoselective synthesis
• Acetylmethyltriphenylarsonium bromide
• 2,2-Dimethyl-1,3-dioxa-5-substituted-benzylidene-4,6-dione, Cis-l-acetyl-2-aryl-6,6-dimethyl-5,7-dioxo-spiro-[2,5]-4,8-octadiones, β,γ-Trans-β-acetyl-γ-aryl-γ-butyrolactones.