1: 81 percent / silica gel, 10percent oxalic acid / CH2Cl2 / 20 h 2: 1.) O3/O2, 2.) CF3COOH / 1.) CH2Cl2, -78 deg C, 2.) CDCl3 View Scheme

2,6-di-tert-butyl-4-methyl-phenol; sulfuric acid; oxygen; silica gel; ozone 1.) CH2Cl2, -78 deg C, 2 min, 2.) CH2Cl2, 22 deg C, overnight; Yield given. Multistep reaction. Yields of byproduct given;

1: 81 percent / silica gel, 10percent oxalic acid / CH2Cl2 / 20 h 2: 1.) O3/O2, 2.) CF3COOH / 1.) CH2Cl2, -78 deg C, 2.) CDCl3 View Scheme

2,6-di-tert-butyl-4-methyl-phenol; sulfuric acid; oxygen; silica gel; ozone 1.) CH2Cl2, -78 deg C, 2 min, 2.) CH2Cl2, 22 deg C, overnight; Yield given. Multistep reaction. Yields of byproduct given;

With  oxalic acid; silica gel in  dichloromethane 20 h;   

Multi-step reaction with 3 steps 1: 2.) 4-(dimethylamino)pyridine (DMAP) / 1.) Et2O, pentane, -78 deg C, 10 min, 2.) Et2O, pentane, RT, 16 h2: 63 percent / Et2NH, n-BuLi / tetrahydrofuran; hexane / 1.) -78 deg C, 4 h, 2.) RT, 4 d3: 1.) LDA / 1.) THF, hexane, from -78 to 50 deg C, 2.5 h, 2.) THF, hexane, RT, 1 h  

Multi-step reaction with 4 steps 1: 1.) n-BuLi, TMEDA / 1.) hexane, RT, 90 min, 2.) hexane, 0 deg, 30 min2: 2.) 4-(dimethylamino)pyridine (DMAP) / 1.) Et2O, pentane, -78 deg C, 10 min, 2.) Et2O, pentane, RT, 16 h3: 63 percent / Et2NH, n-BuLi / tetrahydrofuran; hexane / 1.) -78 deg C, 4 h, 2.) RT, 4 d4: 1.) LDA / 1.) THF, hexane, from -78 to 50 deg C, 2.5 h, 2.) THF, hexane, RT, 1 h  

Multi-step reaction with 2 steps 1: 63 percent / Et2NH, n-BuLi / tetrahydrofuran; hexane / 1.) -78 deg C, 4 h, 2.) RT, 4 d2: 1.) LDA / 1.) THF, hexane, from -78 to 50 deg C, 2.5 h, 2.) THF, hexane, RT, 1 h