Iv. working backwards-identifying the starting carbonyls show which two carbonyl compounds could have been used to synthesize the following compounds by aldol condensation. hint: you should start by identifying the new c-c bond in each compound. v. synthesis involving reactions at the α-carbon of a carbonyl provide the appropriate reagents for each step in the following syntheses. h 3 c h 3 c h 3 c o h o ph o a) b) c) oh oh o o o o o