1: With n-butyllithium; zirconocene dichloride in tetrahydrofuran T=-78 - 20°C; Metallation; 2: With oxonium in tetrahydrofuran T=-20 - 20°C; Hydrolysis; Further stages.;

triphenyl phosphite; ozone in dichloromethane -35 deg C --> room temp., then room temp., overnight;