An Efficient Synthesis of 7,11-diarylspiro[5.5]undecane-1,9-dione by the Michael Condensation Under Ultrasound Irradiation in Aqueous and Organic Two Phase in the Presence of Phase-Transfer Catalyst

Improved synthesis of 7,11-diarylspiro[5.5]undecane-1,9-dione via double Michael condensation of 1,5- bisaryl-1,4-pentadien-3-one with cyclohexanone was carried out in 51-96% yields for 3-12 h in CH2Cl2-H2O in the presence of phase-transfer catalyst under ultrasound irradiation. In comparison with reported methods, the main advantages of the present procedure are shorter reaction time and higher yields.