1: cyclohexylacetylene With tBuOOLi; lithium hexamethyldisilazane in tetrahydrofuran; toluene T=-78 - 0°C; 2.5 h; 2: tri-isopropylsylil trifluoromethane sulfonate With tBuOOLi; lithium hexamethyldisilazane in tetrahydrofuran; toluene T=-78 - 0°C;

2,2,6,6-tetramethyl-piperidine; n-butyllithium; 1,1-dibromomethane in tetrahydrofuran; hexane 1.) -78 deg C, 10 min, 30 deg C, 30 min; 2.) 0 deg C, 3.5 h;

n-butyllithium; 2,2,6,6-tetramethylpiperidinyl-lithium 1)THF, -78 to 25 deg C, 2) -78 to 0 deg C; Yield given. Multistep reaction;

Multistep reaction;