1: 1.) CuCN, Bu3SnH, 2.) n-BuLi / 1.) THF, -20 deg C to room temperature, 4 h, 2.) THF, -78 deg C, 45 min, 3.) THF, -78 deg C, 1 h 2: 89 percent / NaH, 15-crown-5 3: 95 percent / HOAc / tetrahydrofuran; H2O 4: 99 percent / imidazole / dimethylformamide 5: 72 percent / DIBAL / tetrahydrofuran / -78 - 0 °C 6: 88 percent 7: 1.) LiHMDS / 1.) THF, -78 deg C to 0 deg C, 2.) THF, -78 deg C to 0 deg C 8: 78 percent 9: 77 percent / Dess-Martin periodinane, pyridine / CH2Cl2 / Ambient temperature 10: 80 percent / aq. HF / acetonitrile / Ambient temperature 11: 85 percent / Et3N 12: 1.) Bu3SnH, AIBN, 2.) I2 / 1.) benzene, 90 deg C, 1 h, 2.) CH2Cl2, 0 deg C 13: 56 percent / LiI / pyridine / 16 h / 130 °C 14: 1.) EDS, DMAP, DMAP*HCl, 2.) i-Pr2NEt, <(2-furyl)3P>2PdCl2 / 1.) CH2Cl2, room temperature, 5 h, 2.) THF, DMF, room temperature, 7 h 15: 90 percent / TBAF, AcOH / tetrahydrofuran / 3 h / 0 °C 16: 71 percent / HF*pyr, pyridine / tetrahydrofuran / Ambient temperature View Scheme

[PhCW{OSi(OtBu)3}3] in toluene T=20°C; 2 h; Molecular sieve;

1: BuLi, t-BuOK / hexane; tetrahydrofuran / -80 °C 2: -100 °C 4: 2-methyl-propan-2-ol; hexamethylphosphoric acid triamide / 0.5 h / 30 °C View Scheme

N,N,N',N',N'',N''-hexamethylphosphoric triamide; n-butyllithium; potassium tert-butylate; tert-butyl alcohol in tetrahydrofuran; hexane other substituted diynes; Mechanism;

n-butyllithium; potassium tert-butylate in tetrahydrofuran; hexane T=-80°C;

1: NBS; AgF / acetonitrile / 1 h / 20 °C 2: 60 percent / i-Pr2NH / Pd(PPh3)4 / dimethylformamide / 70 h / 20 °C View Scheme

N-bromosuccinmide; silver fluoride in acetonitrile T=20°C; 1 h;

1: 1.) t-BuOK, n-BuLi, 2.) t-BuOH, HMPA / 1.) THF, hexane, from -100 to -30 deg C, 2 h, 2.) THF, hexane, a) -30 deg C, 3 h, b) RT, overnight 2: 85 percent / Br2 / CS2 / 54 h / Heating View Scheme

1: 1.) t-BuOK, n-BuLi, 2.) t-BuOH, HMPA / 1.) THF, hexane, from -100 to -30 deg C, 2 h, 2.) THF, hexane, a) -30 deg C, 3 h, b) RT, overnight 2: 85 percent / Br2 / CS2 / 54 h / Heating 3: 71 percent / Zn, AcOH / 3 h / Heating View Scheme