Titanium-Catalyzed Stereoselective Synthesis of Spirooxindole Oxazolines
摘要:
A regio- and stereoselective cyclization between isatins and 5-methoxyoxazoles has been developed using catalytic titanium(IV) chloride (10 or 20 mol %) to afford spiro[3,3'-oxindoleoxazolines] in excellent yield (up to 99%) and diastereoselectivity (dr >99:1). Substitution at the 4-position of the oxazole controls nucleophilic attack to provide either the 2-oxazoline or 3-oxazoline spirocycle with excellent (>99:1) regiocontrol.
描述了磁性CuFe 2 O 4纳米颗粒在醛与胺盐酸盐的氧化酰胺化中的应用。在温和的条件下,已经以良好的收率合成了各种酰胺。还从其相应的手性胺盐合成了手性酰胺,并且保留了立体化学。特别地,催化剂的磁分离性能非常有效,并且可以替代时间,溶剂和耗能的分离程序。连续五个周期后,催化剂的催化活性保持不变,由于其效率,易处理性和成本效益,使其在环境方面无害且可广泛应用。