Preparation of Bromoacetaldehyde:1,4-dibromo-trans-2-butene(10g, 0.046 mol) was dissolved in dry CH2CI2 (100 ml) and cooled to -780℃ and ozone gas was bubbled until the blue color persisted (~30 min). A nitrogen stream was passed through the solution until the blue color disappeared, giving colorless solution. Triphenyl phosphine (12.9g, 0.046 mol) was added portion wise over a period EPO of 1 hr. The reaction mixture was brought to 0℃ and kept in the refrigerator for 15 hrs. The solvent (CH2CI2) was removed from the reaction mixture (without applying vacuum) and the thick residue was distilled at 400℃ under vacuum (1mm Hg), maintaining the temperature of the receiving flask at -780℃. (during distillation, special care was taken to maintain a cold water circulation (~0°C to - 50℃)). The bromoacetaldehyde(2.8g, yield = 50%) was obtained as a light yellow liquid.
