N,N,N',N,-tetramethylethylenediamine; titanium tetrachloride; zinc in tetrahydrofuran T=25°C; 0.333333 h;

1: 2-(trimethylsilyl)-1,3-dithiane With n-butyllithium in tetrahydrofuran; hexane T=-78 - 0°C; 2: acetaldehyde in tetrahydrofuran; hexane T=-78 - 20°C;

1: 1,3-Dithiane With n-butyllithium in tetrahydrofuran; hexane T=-78 - 0°C; 1.25 h; Inert atmosphere; 2: With chloro-trimethyl-silane in tetrahydrofuran; hexane T=-78 - 20°C; 1.25 h; Inert atmosphere; 3: acetaldehyde Further stages;

n-butyllithium in tetrahydrofuran; hexane 1.) -20 grad C, 1,5 h; 2.) -20 grad C, 1 h, heated 1,5 h;

1: 87 percent / LDA / tetrahydrofuran / -70 degC - RT 2: 1.) nBu4NF / 1.) THF View Scheme