1.1: diisopropylamine; n-butyllithium / hexane; N,N'-dimethyl-N,N'-propyleneurea; tetrahydrofuran / 1 h / -78 °C / Inert atmosphere 1.2: -78 - 25 °C 2.1: diisopropylamine; n-butyllithium / hexane; N,N'-dimethyl-N,N'-propyleneurea; tetrahydrofuran / -78 - 25 °C / Inert atmosphere View Scheme

lithium diisopropyl amide 1.) THF, HMPT, -75 deg C, 40 min, 2.) THF, HMPT, -80 deg C to RT, 1.5 h; Yield given. Multistep reaction. Yields of byproduct given;

1.1: diisopropylamine; n-butyllithium / hexane; N,N'-dimethyl-N,N'-propyleneurea; tetrahydrofuran / 1 h / -78 °C / Inert atmosphere 1.2: -78 - 25 °C 2.1: diisopropylamine; n-butyllithium / hexane; N,N'-dimethyl-N,N'-propyleneurea; tetrahydrofuran / -78 - 25 °C / Inert atmosphere 3.1: water; Ba(OH)2·8H2O / ethanol / Inert atmosphere; Reflux 3.2: 18 - 25 °C / pH 1 - 2 View Scheme

barium dihydroxide; water

iodine; lithium diisopropyl amide 1.) THF, hexane, from -78 to 0 deg C, 2.5 h, 2.) THF, hexane, from -78 deg C to RT; Multistep reaction;

1: 1.) LDA, 2.) I2 / 1.) THF, hexane, from -78 to 0 deg C, 2.5 h, 2.) THF, hexane, from -78 deg C to RT 2: aq. KOH / methanol / Heating 3: 1.) HgO, 2.) Br2 / 1.) CH2Cl2, reflux, irradiation, 2.) CH2Cl2, reflux 4: 1.) tert-BuLi / 1.) THF, pentane, -78 deg C, 5 min, 2.) THF, pentane, from -78 deg C to RT View Scheme

1.1: lithium diisopropyl amide; N,N'-dimethyl-N,N'-propyleneurea / tetrahydrofuran / 1.33 h / -78 °C 1.2: -78 - 20 °C 2.1: lithium diisopropyl amide; N,N'-dimethyl-N,N'-propyleneurea / tetrahydrofuran / 2.33 h / -78 - 20 °C View Scheme