potassium carbonate in N,N-dimethyl-formamide T=60°C; 2.5 h;

potassium carbonate in N-methyl-acetamide; ethyl acetate

1.1: 3-chloroperoxybenzoic acid / CH2Cl2 / 72 h / 0 - 20 °C 1.2: 92 percent / 2 M NaOH / diethyl ether 2.1: 69 percent / K2CO3 / dimethylformamide / 2.5 h / 60 °C View Scheme

1: Methyltriphenylphosphonium bromide With potassium tert-butylate in tetrahydrofuran Wittig reaction; 2 h; 2: 4-Methoxy-3-(2-oxocyclopentyloxy)bromobenzene in tetrahydrofuran 1 h; Further stages.;