1: 49 percent / CH2Cl2 / 10 °C 2: 92 percent / imidazole / dimethylformamide / 5 h / 25 °C 3: 1.) 1,3-dibromo-5,5-dimethyl hydantoin, collidine, AIBN; 2.) bis-tetrabutylammoniumdichromate / 1.) hexane, CH2Cl2, reflux, 20 min; 2.) CHCl3, reflux, 3 h 4: 84 percent / n-butyric acid, tetrabutylammonium fluoride / tetrahydrofuran / 2 h / 20 °C 5: 73 percent / LiAlH4, AlCl3 / tetrahydrofuran / 1 h / -60 °C 6: 51 mg / KOH / methanol; H2O / 70 h / 85 °C View Scheme

1: 49 percent / CH2Cl2 / 10 °C 2: 92 percent / imidazole / dimethylformamide / 5 h / 25 °C 3: 1.) 1,3-dibromo-5,5-dimethyl hydantoin, collidine, AIBN; 2.) bis-tetrabutylammoniumdichromate / 1.) hexane, CH2Cl2, reflux, 20 min; 2.) CHCl3, reflux, 3 h 4: 84 percent / n-butyric acid, tetrabutylammonium fluoride / tetrahydrofuran / 2 h / 20 °C 5: 73 percent / LiAlH4, AlCl3 / tetrahydrofuran / 1 h / -60 °C View Scheme