Lewis base catalyzed Mannich-type reactions between trimethylsilyl enol ethers and aldimines.
Lewis base catalyzed Mannich-type reactions between trimethylsilyl enol ethers and aldimines.
复制标题
路易斯碱催化三甲基硅烯醇醚和醛亚胺之间的曼尼希型反应。
作者：
H. Fujisawa;Eiki Takahashi;T. Mukaiyama
本文报道了刘易斯碱催化的三甲基硅烯醇醚与N-对甲苯磺酰醛亚胺的Mannich型反应。发现由酰胺或酰亚胺如苯甲酰胺锂或邻苯二甲酰亚胺钾产生的氮阴离子在室温下在DMF中是有效的刘易斯碱催化剂，以良好至高产率提供相应的β-氨基羰基化合物;还发现由羧酸如乙酸锂产生的氧阴离子在干燥DMF中是有效的。醛亚胺和各种三甲基甲硅烷基（TMS）烯醇醚如甲硅烷基烯酮缩醛之间的上述乙酸锂催化的曼尼希型反应甚至在含水DMF中也顺利进行。然后，研究了刘易斯碱催化TMS烯醇醚、对甲苯磺酰胺和具有吸电子基团的芳香醛如对硝基苯甲醛的三组分Mannich型反应。反应顺利进行，以良好的产率得到相应的β-氨基酯。此外，发现羧酸铵如乙酸四丁基铵或苯甲酸四丁基铵在上述曼尼希型反应中是更有效的刘易斯碱催化剂。合成在各种溶剂中在较低温度下进行。醛亚胺与硫酯生成的TMS烯醇醚和各种酮如苯丙酮或环己酮之间的反应也顺利进行，以高产率提供相应的β-氨基羰基化合物，具有良好至高的反选择性。
Lewis base catalyzed Mannich-type reaction between trimethylsilyl enol ethers and N-tosylaldimines is described. Nitrogen anions generated from amides or imides such as lithium benzamide or potassium phthalimide are found to be effective Lewis base catalysts in DMF at room temperature to afford the corresponding beta-amino carbonyl compounds in good to high yields; the oxygen anion generated from carboxylic acids such as lithium acetate was also found to be effective in dry DMF. The above-mentioned lithium acetate-catalyzed Mannich-type reaction between aldimines and various trimethylsilyl (TMS) enol ethers such as silyl ketene acetal proceeded smoothly even in water-containing DMF. Then, Lewis base catalyzed three-component Mannich-type reactions of TMS enol ether, tosylamide, and aromatic aldehyde having electron-withdrawing group such as p-nitrobenzaldehyde were investigated. The reaction proceeded smoothly to afford the corresponding beta-amino ester in good yield. Further, ammonium carboxylates such as tetrabutyl ammonium acetate or tetrabutyl ammonium benzoate were found to be more effective Lewis base catalysts in the above-mentioned Mannich-type reaction. The synthesis proceeded in various solvents at lower temperatures. The reaction between aldimines and TMS enol ethers generated from thioester and various ketones such as propiophenone or cyclohexanone also proceeded smoothly to afford the corresponding beta-amino carbonyl compounds in high yields with good to high anti-selectivities.