2: aq. KOH / ethanol 3: (i) Py, (ii) LiAlH4 4: H2 View Scheme

1: methyllithium With copper(l) iodide in anhydrous butyl ether T=-20°C; 0.166667 h; 2: toluene-4-sulfonic acid cyclopent-3-enyl ester in anhydrous butyl ether T=-20°C; 10 h;

1: N-(ethylidene)-cyclohexylamine With n-butyllithium; diisopropylamine in tetrahydrofuran; hexane T=0°C; Addition; 1 h; 2: toluene-4-sulfonic acid cyclopent-3-enyl ester in tetrahydrofuran; hexane T=0°C; Addition; 18 h; Further stages.;

1: n-propyl-magnesium bromide With copper(l) iodide in tetrahydrofuran T=-78°C; 1 h; 2: toluene-4-sulfonic acid cyclopent-3-enyl ester in tetrahydrofuran T=-78 - -20°C;