1,8-diazabicyclo[5.4.0]undec-7-ene in tetrahydrofuran T=20°C;

tri-n-butyltin methoxide; bis (triortho-tolylphosphine)palladium(II) chloride in toluene T=100°C; 22 h;

in tetrahydrofuran T=-23°C; 1 h;

2-(tert-butyl)-1,1,3,3-tetramethylguanidine in tetrahydrofuran 21 h; Ambient temperature;

in tetrahydrofuran 3 h; Ambient temperature;

2,3,11,12-dicyclohexano-1,4,7,10,13,16-hexaoxacyclo-octadecane; 2-(tert-butyl)-1,1,3,3-tetramethylguanidine in tetrahydrofuran 56 h; Ambient temperature;

2-(tert-butyl)-1,1,3,3-tetramethylguanidine in tetrahydrofuran 15 h; Ambient temperature;

2-(tert-butyl)-1,1,3,3-tetramethylguanidine in tetrahydrofuran 15 h; Ambient temperature;

1.1: NaH / dimethylformamide / 0 - 20 °C 1.2: 93 percent / 20 °C 2.1: 75 percent / p-TsOH / dioxane / 110 °C 3.1: HgCl2 / methanol; CH2Cl2 / 20 °C 3.2: DBU / tetrahydrofuran / 20 °C 4.1: BuLi / tetrahydrofuran; hexane / 0.33 h / -78 °C 4.2: 53 percent / tetrahydrofuran / -78 - -30 °C 5.1: LHMDS / tetrahydrofuran / -78 °C 5.2: 70 percent / MoOPH / tetrahydrofuran / -78 °C 6.1: 100 percent / DBU / tetrahydrofuran / 20 °C View Scheme

1.1: HgCl2 / methanol; CH2Cl2 / 20 °C 1.2: DBU / tetrahydrofuran / 20 °C 2.1: BuLi / tetrahydrofuran; hexane / 0.33 h / -78 °C 2.2: 53 percent / tetrahydrofuran / -78 - -30 °C 3.1: LHMDS / tetrahydrofuran / -78 °C 3.2: 70 percent / MoOPH / tetrahydrofuran / -78 °C 4.1: 100 percent / DBU / tetrahydrofuran / 20 °C View Scheme