1: 83 percent 2: 0.1 N (CH3)3CONa / diethyl ether; 2-methyl-propan-2-ol / 20 h / Ambient temperature 3: 61 percent / 10percent H2SO4 / methanol / 24 h / Ambient temperature 4: 1) mesitol, molecular sieve, 2) K, aniline / 1) pyridine, anh. methylcyclohexane, 10 h, irradiation, 2) liq. NH3 5: 64 percent / diisobutylaluminiumhydride / toluene View Scheme

4: Irradiation View Scheme

1: 83 percent 2: 0.1 N (CH3)3CONa / diethyl ether; 2-methyl-propan-2-ol / 20 h / Ambient temperature 3: 61 percent / 10percent H2SO4 / methanol / 24 h / Ambient temperature 4: 1) mesitol, molecular sieve, 2) K, aniline / 1) pyridine, anh. methylcyclohexane, 10 h, irradiation, 2) liq. NH3 View Scheme

4: Irradiation View Scheme

1: 83 percent 2: 0.1 N (CH3)3CONa / diethyl ether; 2-methyl-propan-2-ol / 20 h / Ambient temperature 3: 61 percent / 10percent H2SO4 / methanol / 24 h / Ambient temperature 5: 49.4 mg / Cr(VI)-oxid, 95percent acetic acid / acetic acid / 2 h / Ambient temperature View Scheme