Mixed Picolinate and Quinaldinate Iron(III) Complexes for the Catalytic Oxidation of Alcohols with Hydrogen Peroxide
作者:Shinji Tanaka、Yoshihiro Kon、Atsuko Ogawa、Yumiko Uesaka、Masanori Tamura、Kazuhiko Sato
DOI:10.1002/cctc.201600362
日期:2016.9.21
of Fe mixed picolinate and quinaldinate complexes that catalyze the H2O2 oxidation of alcohols are presented. The Fe catalysts are generated in situ by simple mixing of iron acetate with 6‐methylpicolinic acid (6‐MepicH) and 4‐chloropicolinic acid (4‐ClpicH); they showed high catalytic activity for H2O2 oxidation of 1‐phenylethanol to acetophenone. Fe complexes generated in situ as precatalysts were
提出了一系列Fe混合的吡啶甲酸和喹啉酸配合物,它们催化醇的H 2 O 2氧化。Fe催化剂是通过将乙酸铁与6-甲基吡啶甲酸(6-MepicH)和4-氯吡啶甲酸(4-ClpicH)简单混合而原位产生的。它们对1-苯基乙醇的H 2 O 2氧化为苯乙酮具有很高的催化活性。成功地分离了原位生成的铁络合物作为前催化剂,并对其结构进行了表征。根据铁络合物的单晶X射线分析和电化学测量,发现吡啶甲酸和/或喹啉配体的不稳定性和Fe III的氧化还原电势是催化反应的重要因素。
Practical Iron-Catalyzed Hydrogen Peroxide Epoxidation of Aromatic Olefins using a Combination of Two Kinds of Simple Picolinate Ligands under Halide-Free Reaction Conditions
作者:Takefumi Chishiro、Yoshihiro Kon、Takuya Nakashima、Midori Goto、Kazuhiko Sato
DOI:10.1002/adsc.201300774
日期:2014.2.10
AbstractHigh‐yield syntheses of epoxides using an iron complex having two types of picolinates in the presence of hydrogen peroxide under halide‐free reaction conditions were achieved. The reaction is very simple. The complex, prepared with iron(II) acetate, 2‐picolinic acid (picH) and 6‐methyl‐2‐picolinic acid (Me‐picH) in acetonitrile, quickly catalyzed an epoxidation of styrene (15 min.) at 25 °C with 1.40 equivalents of 35% aqueous hydrogen peroxide solution to afford styrene oxide in 95% yield with 96% selectivity. We also carried out a 100‐g scale epoxidation of styrene using 1.25 equivalents of 35% aqueous hydrogen peroxide solution with the iron catalyst to give styrene oxide in 80% isolated yield. The developed iron catalyst was efficiently applicable to the epoxidation of various aromatic olefins to give the corresponding epoxides in high yields. To obtain more information about this catalytic system, the pre‐catalyst of this reaction was isolated and the structure was determined to be [Fe(pic)(Me‐pic)2] by single‐crystal X‐ray analysis. The [Fe(pic)(Me‐pic)2] catalyst effectively epoxidized styrene to styrene oxide in 93% yields. The system should be suitable for large‐scale preparations of aromatic olefins due to the employment of simple ligands with halide‐ and amine‐free reaction conditions.magnified image