1: carbonic acid 3-cyclohexyloxy-prop-2-ynyl ester ethyl ester With (η2-propene)Ti(O-i-Pr)2 in diethyl ether T=-50 - -40°C; Metallation; 1.5 h; 2: benzaldehyde in diethyl ether T=-40 - 0°C; Addition; 6 h; 3: With sodium hydride in tetrahydrofuran T=0 - 20°C; Reduction;