1: 3-chloro-1-(p-toluenesulfonyl)pyrrole With n-butyllithium in tetrahydrofuran; hexane T=-78°C; Metallation; 1.25 h; 2: N,N-dimethyl-formamide in tetrahydrofuran T=-78°C; Formylation; detosylation; 1 h;

1: 3-chloro-1-(p-toluenesulfonyl)pyrrole With n-butyllithium in tetrahydrofuran; hexane T=-78°C; Metallation; 1 h; 2: N,N-dimethyl-formamide in tetrahydrofuran T=-78°C; Formylation; 1 h;