barium permanganate in dichloromethane 3.5 h; Ambient temperature;

1: dimethyl(1,1-dimethylethyl)(2-propynyloxy)silane With methyl lithium LiBr complex in tetrahydrofuran; diethyl ether T=0°C; 0.25 h; 2: N,N-dimethyl-formamide in tetrahydrofuran; diethyl ether T=20°C; 1 h; Further stages.;

1: imidazole 2: Dess-Martin periodinane View Scheme

n-butyllithium; hexane in tetrahydrofuran -30 deg, 1.5 h --> -78 deg C, 2 h --> -30 deg C, 1 h;