2: 94 percent / imidazole / dimethylformamide / 4 h / 25 °C 3: 1.) n-butyllithium, 2.) Gilman reagent, cuprrous cyanide, HMPA 4: H2, triethylamine / Lindlar catalyst / hexane / 760 Torr 5: tetra-n-butylammonium fluoride / tetrahydrofuran / 25 °C 6: 25 °C / saponification View Scheme