Toward the optimization of continuous-flow aldol and α-amination reactions by means of proline-functionalized silicon packed-bed microreactors

The activity and stability under flow conditions of covalently and non-covalently silica supported proline and proline-like organocatalysts is herein described. The slow aldol reaction of cyclohexanone with p-nitro benzaldehyde and the fast alpha-amination of isovaleraldehyde with dibenzyl azodicarboxylate have been selected as model reactions for this study. Prospects and limitations of the disclosed continuous-flow organocatalytic approach are widely discussed. (C) 2010 Elsevier Ltd. All rights reserved.