18-crown-6 ether; potassium tert-butylate in tetrahydrofuran T=-78 - 0°C; Horner-Wadsworth-Emmons Olefination; 2 h; Reagent/catalystTemperature; Overall yield = 82 percent; stereoselective reaction;

18-crown-6 ether; potassium tert-butylate in tetrahydrofuran T=-78°C; Horner-Wadsworth-Emmons Olefination; 2 h; stereoselective reaction;

18-crown-6 ether; potassium tert-butylate in tetrahydrofuran T=-78 - 0°C; Horner-Wadsworth-Emmons Olefination; 2 h; Reagent/catalystTemperature; Overall yield = 82 percent; stereoselective reaction;

potassium tert-butylate in tetrahydrofuran T=0°C; Horner-Wadsworth-Emmons Olefination; 2 h; Reagent/catalystTemperature; Overall yield = 88 percent; stereoselective reaction;