4-(N,N-dimethlyamino)pyridine in tetrahydrofuran; N,N-dimethyl-formamide Heating;

1: 1.) CuI / 1.) Et2O 2: 75 percent / TEA,DMAP / tetrahydrofuran; dimethylformamide / Heating View Scheme

dimethylsulfide; ozone 1.) MeOH, - 60 deg C; Yield given. Multistep reaction;

1: 1.) O3, 2.) Me2S / 1.) MeOH, - 60 deg C 2: 56 percent / KN(Me4Si)2, 18-C-6 / tetrahydrofuran 3: dibal / diethyl ether / -78 - 0 °C 4: TEA, DMAP / CH2Cl2 5: 48percent aq. HF / acetonitrile / 0 °C 6: 81 percent / NaHCO3, I2 / CH2Cl2 / 1.5 h / 0 °C View Scheme

1: 1.) O3, 2.) Me2S / 1.) MeOH, - 60 deg C 2: 56 percent / KN(Me4Si)2, 18-C-6 / tetrahydrofuran View Scheme

1: 1.) O3, 2.) Me2S / 1.) MeOH, - 60 deg C 2: 56 percent / KN(Me4Si)2, 18-C-6 / tetrahydrofuran 3: dibal / diethyl ether / -78 - 0 °C 4: TEA, DMAP / CH2Cl2 5: 48percent aq. HF / acetonitrile / 0 °C 6: 81 percent / NaHCO3, I2 / CH2Cl2 / 1.5 h / 0 °C 7: 54 percent / 1.) AgBF4, 2.) H2O / 48 h / 21 °C View Scheme

1: 1.) O3, 2.) Me2S / 1.) MeOH, - 60 deg C 2: 56 percent / KN(Me4Si)2, 18-C-6 / tetrahydrofuran 3: dibal / diethyl ether / -78 - 0 °C View Scheme

1: 1.) O3, 2.) Me2S / 1.) MeOH, - 60 deg C 2: 56 percent / KN(Me4Si)2, 18-C-6 / tetrahydrofuran 3: dibal / diethyl ether / -78 - 0 °C View Scheme

1: 1.) O3, 2.) Me2S / 1.) MeOH, - 60 deg C 2: 56 percent / KN(Me4Si)2, 18-C-6 / tetrahydrofuran 3: dibal / diethyl ether / -78 - 0 °C 4: TEA, DMAP / CH2Cl2 View Scheme