performed on precoated silica gel plates (0.25-mm 60 F-254 E. Merck). The products were pu rified by flash column chro-matography on silica gel 60 (Merck, 230 - 400 mesh). THF was dried over sodium benzophenone prior to use. Commercially available compounds and solvents were used without previous purification.
使用四甲基
硅烷作为内标的溶液。在预涂
硅胶板(0.25-mm 60 F-254 E. Merck)上进行分析薄层色谱。产物通过
硅胶60(Merck,230-400目)上的快速柱色谱法纯化。THF在使用前用
二苯甲酮钠干燥。使用市售的化合物和溶剂而无需事先纯化。