Organocatalyzed Mannich reaction: electrochemically synthesized prolinated carbon dots vs. prolinated grapheneoxide

Background: L-Pro was previously used as an organocatalyst in the Mannich reaction under homogeneous conditions; a recoverable catalyst could be useful; this is the first report on the application of prolinated carbon dots to the Mannich reaction. Methods: Prolinated carbon dots were synthesized electrochemically using a bottom-up approach; they were characterized and used in the Mannich reaction in water using only a slight excess of ketone; for a useful comparison, L-proline decorated graphene oxide was synthesized. Results: The characterization of carbon dots and functionalized graphene oxide confirmed the presence of L-Pro on their surface; their use in the Mannich reaction gave good yields when carrying out the reaction in water; a possible recycle of the catalyst was demonstrated. Conclusions: Both electrochemically synthesized prolinated carbon dots and prolinated graphene oxide acted as organocatalysts in the Mannich reaction. Higher yields were obtained using L-Pro-CDs obtained under galvanostatic conditions.