1: (phenylsulfonyl)methane; methyloxirane With N,N'-dimethyl-N,N'-propyleneurea; n-butyllithium in tetrahydrofuran; hexane T=25°C; Addition; Ring cleavage; 0.25 h; 2: tert-butyldimethylsilyl chloride With triethylamine in tetrahydrofuran T=0°C; Substitution; Silylation;

triethylamine in tetrahydrofuran T=0°C; Yield given;

1: 1) n-BuLi, 2) DMPU / 1) THF, -78 deg C, 2) RT 2: NEt3 / tetrahydrofuran / 0 °C View Scheme

1.1: n-BuLi / tetrahydrofuran; hexane / -78 °C 1.2: 89 percent / n-BuLi / tetrahydrofuran; hexane / 0.08 h / -78 °C 2.1: potassium tert-butoxide / tetrahydrofuran / 25 °C 2.2: aq. HF / acetonitrile / 1 h / 25 °C 3.1: 42 percent / t-BuOK / 2-methyl-propan-2-ol; tetrahydrofuran / 0.25 h / 25 °C View Scheme