1: metachloroperbenzoic acid With 2,2,6,6-tetramethyl-piperidine; n-butyllithium in tetrahydrofuran T=-50°C; 4 h; 2: N,N-dimethyl-formamide in tetrahydrofuran T=-50 - 20°C; Further stages.;

(oxidation);

1: (i) (diazotization), (ii) Cu2Cl2 2: (oxidation) View Scheme