| The aldol reaction is an exceptionally useful strategic C-C bond-forming reaction for the stereoselective construction of cyclic and acyclic molecules. The synthetic value of the aldol reactions has been proven by their application in the total synthesis of natural products. The advantages of proline based aldolization are that the methodology is metal free and that both enantiomers of the catalyst are cheap and easily available. Proline catalysed aldolization show both high yields and stereoselectivity. The catalytic enantioselective version of this reaction has received considerable attention in recent years.It was reported that using the L-proline catalysed asymmetric Aldol reation can sythesize nitrogen heterocyclic ring by the intramolecular nucleophilic substitution, and using this method can also make the natural biologic hygroline. In this paper, 4-aminobutyric acid was used as the base material and studied the synthetic methods of benzyl, BOC and Cbz protecting aminobutyl aldehyde, respectively. The asymmetric aldol condensation was successfully processed by the reaction of acetone and benzyl protecting aminobutyl aldehyde undering the catalysis of L-proline. And finally we found that undering the catalysis of L-proline, the anhydride materials which are easily ringing formed hemiacetal cannot react with acetone using asymmetric Aldo reaction. |
