新颖有机催化剂的合成及催化不对称直接Aldol反应研究

以N-苄氧羰基-(S)-脯氨酸和5-(1-氨基烷基)四氮唑(烷基: 甲基、乙基、2-苯基乙基)为原料, 经两步反应合成了3个新颖的有机催化剂: (S)-5-脯氨酰胺基甲基四氮唑(3a), (S,S)-5-(1-脯氨酰胺基乙基)四氮唑(3b)和(S,S)-5-(1-脯氨酰胺 基-2-苯基乙基)四氮唑(3c), 并首次将其用于催化丙酮和含吸电子基芳香醛的不对称直接aldol反应. 在室温条件下, 催化剂3b表现出较好的催化活性, 产物的ee值最高可达96%.

Studies on Synthesis of Novel Chiral Organocatalysts and Its Evaluations for Asymmetric Direct Aldol Reactions

Three novel organocatalysts (S)-5-prolylaminomethyltetrazole (3a), (S,S)-5-(1-prolylaminoethyl) tetrazole (3b) and (S,S)-5-(1-prolylamino-2-phenylethyl)tetrazole (3c) were readily prepared from N-benzyloxycarbonyl-(S)-proline and corresponding 5-(1-aminoalkyl)tetrazol (alkyl: methyl, ethyl and 2-phenylethyl) by the known reaction sequences in just two steps. Their catalytic performances were first evaluated in the asymmetric direct aldol reactions of acetone with electron-deficient aromatic aldehydes. At room temperature, the catalyst 3b displayed the efficient reactivity and the enantiomeric excess (ee) value of the products was up to 96%.