1: 4-phenoxybutyl chloride With di(tert-butyl)-biphenyl; lithium in tetrahydrofuran T=-78°C; Metallation; 0.5 h; 2: pivalaldehyde T=20°C; Addition; 1.5 h; 3: acetone T=-78°C; Addition; 0.0833333 h; Further stages.;