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以(R)-BINOL为原料合成NNN三齿钳形手性配体,研究了其与各种金属盐形成金属络合物在室温下原位催化芳香醛与硝基甲烷的不对称Henry反应.考察了不同金属盐、溶剂、碱对反应的影响,优化得到最佳反应条件为:CuOTf/NNN三齿配体(1∶1)催化体系,催化剂用量为10 mol%,甲醇作溶剂,室温反应5 d,收率57%,对映选择性80%ee;加入10 mol%有机碱(Me3Si)2MeN后反应速度加快,对映选择性略有降低,室温反应17 h,收率37%,ee值67%.此催化体系适用于大部分的芳香醛,收率中等,对映选择性可达75%ee.
The asymmetric Henry reaction of aromatic aldehydes and nitromethane catalyzed by metal complexes with various metal salts was studied in situ using (R) -BINOL as starting material. The effects of different metal salts, solvents and alkalis on the reaction were investigated. The optimal reaction conditions were as follows: CuOTf / NNN tridentate ligand (1: 1) catalyst system with 10 mol% catalyst, methanol as solvent, 5 d, the yield was 57% and the enantioselectivity was 80% ee. After 10 mol% organic base (Me3Si) 2MeN was added, the reaction speed increased and the enantioselectivity decreased slightly. The reaction was carried out at room temperature for 17 h with a yield of 37% Value of 67%. This catalytic system is suitable for most of the aromatic aldehydes, medium yield, enantioselectivity up to 75% ee.