The development of diastereoselective, catalytic methodologies for synthesis of Mannich products presents specific promise for synthetic applications. Only highly reactive aldehydes such as formaldehyde and acetaldehyde, secondary amine, have been ruled out of the classical Mannich reaction. Highly stereoselective Mannich reactions have been extensively studied and reported. The most powerful enantioselective and diastereoselective C-C bond forming reactions include the asymmetric Mannich reaction such as oxidative and reductive Mannichreaction. In oxidative type, an oxidizing agent such as oxygen, air, etc. is used. Whereas in reductive Mannich reaction, a reducing agent produces enolate for the generation of a reactive iminium ion. Cross-dehydrogenative coupling reactions (CDC) are a method for generating more complex amines from simpler materials by oxidatively functionalizing amine -CH bonds. Besides, the redox-Mannich reaction uses the same raw materials but includes an isomerization step that makes it simple to create ring-substituted -amino ketones. In this review article, we have tried to study the research that has been done in recent years for oxidative and reductive Mannich reactions.

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