Cross-aldol condensation: Aldol conden-sation of a mixture of two different aldehydes or ketones each containing an α-hydrogen gives a mixture of four products. Two products are made up of two molecules of same carbonyl compounds and are same as in case of simple aldol condensation. The other two products arise from the reaction between one molecule each of two different carbonyl compounds. These are called cross aldol conden-sation products and the reaction leading to formation of these products is known as cross-aldol conden-sation. Example: