First success of catalytic epoxidation of olefins by an electron-rich iron(III) porphyrin complex and H2O2

Imidazole effect on the activation of H2O2 by iron porphyrin complexes in aprotic solvent

Wonwoo Nam, Ha J. Lee, So Young Oh, Cheal Kim, Ho Gyeom Jang

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Abstract

An electron-rich iron(III) porphyrin complex (meso- tetramesitylporphinato)iron(III) chloride [Fe(TMP)Cl], was found to catalyze the epoxidation of olefins by aqueous 30% H2O2 when the reaction was carried out in the presence of 5-chloro-1-methylimidazole (5-Cl-1-MeIm) in aprotic solvent. Epoxides were the predominant products with trace amounts of allylic oxidation products, indicating that Fenton-type oxidation reactions were not involved in the olefin epoxidation reactions. cis-Stilbene was stereospecifically oxidized to cis-stilbene oxide without giving isomerized trans-stilbene oxide product, demonstrating that neither hydroperoxy radical (HOO·) nor oxoiron(IV) porphyrin [(TMP)Fe(IV) = O] was responsible for the olefin epoxidations. We also found that the reactivities of other iron(III) porphyrin complexes such as (meso-tetrakis(2,6- dichlorophenyl)porphinato)iron(III) chloride [Fe(TDCPP)Cl], (meso- tetrakis(2,6-difluorophenyl)porphinato)iron(III) chloride [Fe(TDFPP)Cl], and (meso-tetrakis(pentafluorophenyl)porphinato)iron(III) chloride [Fe(TPFPP)Cl] were significantly affected by the presence of the imidazole in the epoxidation of olefins by H2O2. These iron porphyrin complexes did not yield cyclohexene oxide in the epoxidation of cyclohexene by H2O2 in the absence of 5-Cl-1-MeIm in aprotic solvent; however, addition of 5-Cl-1-MeIm to the reaction solutions gave high yields of cyclohexene oxide with the formation of trace amounts of allylic oxidation products. We proposed, on the basis of the results of mechanistic studies, that the role of the imidazole is to decelerate the O-O bond cleavage of an iron(III) hydroperoxide porphyrin (or H2O2-iron(III) porphyrin adduct) and that the intermediate transfers its oxygen to olefins prior to the O-O bond cleavage. (C) 2000 Elsevier Science S.A.

Original languageEnglish
Pages (from-to)219-225
Number of pages7
JournalJournal of Inorganic Biochemistry
Volume80
Issue number3-4
DOIs
Publication statusPublished - 2000 Jul 1

Fingerprint

Epoxidation
Porphyrins
Alkenes
Iron
Chemical activation
Electrons
Oxidation
imidazole
Thymidine Monophosphate
Stilbenes
Epoxy Compounds
Hydrogen Peroxide
(meso-tetramesitylporphinato)iron(III) chloride

Keywords

  • Biomimetic oxidation
  • Epoxidations
  • Hydrogen peroxide
  • Iron porphyrins
  • O-O activation

ASJC Scopus subject areas

  • Biochemistry
  • Inorganic Chemistry

Cite this

@article{a93d3ea4a6df4795be67f5960e304f33,
title = "First success of catalytic epoxidation of olefins by an electron-rich iron(III) porphyrin complex and H2O2: Imidazole effect on the activation of H2O2 by iron porphyrin complexes in aprotic solvent",
abstract = "An electron-rich iron(III) porphyrin complex (meso- tetramesitylporphinato)iron(III) chloride [Fe(TMP)Cl], was found to catalyze the epoxidation of olefins by aqueous 30{\%} H2O2 when the reaction was carried out in the presence of 5-chloro-1-methylimidazole (5-Cl-1-MeIm) in aprotic solvent. Epoxides were the predominant products with trace amounts of allylic oxidation products, indicating that Fenton-type oxidation reactions were not involved in the olefin epoxidation reactions. cis-Stilbene was stereospecifically oxidized to cis-stilbene oxide without giving isomerized trans-stilbene oxide product, demonstrating that neither hydroperoxy radical (HOO·) nor oxoiron(IV) porphyrin [(TMP)Fe(IV) = O] was responsible for the olefin epoxidations. We also found that the reactivities of other iron(III) porphyrin complexes such as (meso-tetrakis(2,6- dichlorophenyl)porphinato)iron(III) chloride [Fe(TDCPP)Cl], (meso- tetrakis(2,6-difluorophenyl)porphinato)iron(III) chloride [Fe(TDFPP)Cl], and (meso-tetrakis(pentafluorophenyl)porphinato)iron(III) chloride [Fe(TPFPP)Cl] were significantly affected by the presence of the imidazole in the epoxidation of olefins by H2O2. These iron porphyrin complexes did not yield cyclohexene oxide in the epoxidation of cyclohexene by H2O2 in the absence of 5-Cl-1-MeIm in aprotic solvent; however, addition of 5-Cl-1-MeIm to the reaction solutions gave high yields of cyclohexene oxide with the formation of trace amounts of allylic oxidation products. We proposed, on the basis of the results of mechanistic studies, that the role of the imidazole is to decelerate the O-O bond cleavage of an iron(III) hydroperoxide porphyrin (or H2O2-iron(III) porphyrin adduct) and that the intermediate transfers its oxygen to olefins prior to the O-O bond cleavage. (C) 2000 Elsevier Science S.A.",
keywords = "Biomimetic oxidation, Epoxidations, Hydrogen peroxide, Iron porphyrins, O-O activation",
author = "Wonwoo Nam and Lee, {Ha J.} and Oh, {So Young} and Cheal Kim and Jang, {Ho Gyeom}",
year = "2000",
month = "7",
day = "1",
doi = "10.1016/S0162-0134(00)00085-4",
language = "English",
volume = "80",
pages = "219--225",
journal = "Journal of Inorganic Biochemistry",
issn = "0162-0134",
publisher = "Elsevier Inc.",
number = "3-4",

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TY - JOUR

T1 - First success of catalytic epoxidation of olefins by an electron-rich iron(III) porphyrin complex and H2O2

T2 - Imidazole effect on the activation of H2O2 by iron porphyrin complexes in aprotic solvent

AU - Nam, Wonwoo

AU - Lee, Ha J.

AU - Oh, So Young

AU - Kim, Cheal

AU - Jang, Ho Gyeom

PY - 2000/7/1

Y1 - 2000/7/1

N2 - An electron-rich iron(III) porphyrin complex (meso- tetramesitylporphinato)iron(III) chloride [Fe(TMP)Cl], was found to catalyze the epoxidation of olefins by aqueous 30% H2O2 when the reaction was carried out in the presence of 5-chloro-1-methylimidazole (5-Cl-1-MeIm) in aprotic solvent. Epoxides were the predominant products with trace amounts of allylic oxidation products, indicating that Fenton-type oxidation reactions were not involved in the olefin epoxidation reactions. cis-Stilbene was stereospecifically oxidized to cis-stilbene oxide without giving isomerized trans-stilbene oxide product, demonstrating that neither hydroperoxy radical (HOO·) nor oxoiron(IV) porphyrin [(TMP)Fe(IV) = O] was responsible for the olefin epoxidations. We also found that the reactivities of other iron(III) porphyrin complexes such as (meso-tetrakis(2,6- dichlorophenyl)porphinato)iron(III) chloride [Fe(TDCPP)Cl], (meso- tetrakis(2,6-difluorophenyl)porphinato)iron(III) chloride [Fe(TDFPP)Cl], and (meso-tetrakis(pentafluorophenyl)porphinato)iron(III) chloride [Fe(TPFPP)Cl] were significantly affected by the presence of the imidazole in the epoxidation of olefins by H2O2. These iron porphyrin complexes did not yield cyclohexene oxide in the epoxidation of cyclohexene by H2O2 in the absence of 5-Cl-1-MeIm in aprotic solvent; however, addition of 5-Cl-1-MeIm to the reaction solutions gave high yields of cyclohexene oxide with the formation of trace amounts of allylic oxidation products. We proposed, on the basis of the results of mechanistic studies, that the role of the imidazole is to decelerate the O-O bond cleavage of an iron(III) hydroperoxide porphyrin (or H2O2-iron(III) porphyrin adduct) and that the intermediate transfers its oxygen to olefins prior to the O-O bond cleavage. (C) 2000 Elsevier Science S.A.

AB - An electron-rich iron(III) porphyrin complex (meso- tetramesitylporphinato)iron(III) chloride [Fe(TMP)Cl], was found to catalyze the epoxidation of olefins by aqueous 30% H2O2 when the reaction was carried out in the presence of 5-chloro-1-methylimidazole (5-Cl-1-MeIm) in aprotic solvent. Epoxides were the predominant products with trace amounts of allylic oxidation products, indicating that Fenton-type oxidation reactions were not involved in the olefin epoxidation reactions. cis-Stilbene was stereospecifically oxidized to cis-stilbene oxide without giving isomerized trans-stilbene oxide product, demonstrating that neither hydroperoxy radical (HOO·) nor oxoiron(IV) porphyrin [(TMP)Fe(IV) = O] was responsible for the olefin epoxidations. We also found that the reactivities of other iron(III) porphyrin complexes such as (meso-tetrakis(2,6- dichlorophenyl)porphinato)iron(III) chloride [Fe(TDCPP)Cl], (meso- tetrakis(2,6-difluorophenyl)porphinato)iron(III) chloride [Fe(TDFPP)Cl], and (meso-tetrakis(pentafluorophenyl)porphinato)iron(III) chloride [Fe(TPFPP)Cl] were significantly affected by the presence of the imidazole in the epoxidation of olefins by H2O2. These iron porphyrin complexes did not yield cyclohexene oxide in the epoxidation of cyclohexene by H2O2 in the absence of 5-Cl-1-MeIm in aprotic solvent; however, addition of 5-Cl-1-MeIm to the reaction solutions gave high yields of cyclohexene oxide with the formation of trace amounts of allylic oxidation products. We proposed, on the basis of the results of mechanistic studies, that the role of the imidazole is to decelerate the O-O bond cleavage of an iron(III) hydroperoxide porphyrin (or H2O2-iron(III) porphyrin adduct) and that the intermediate transfers its oxygen to olefins prior to the O-O bond cleavage. (C) 2000 Elsevier Science S.A.

KW - Biomimetic oxidation

KW - Epoxidations

KW - Hydrogen peroxide

KW - Iron porphyrins

KW - O-O activation

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U2 - 10.1016/S0162-0134(00)00085-4

DO - 10.1016/S0162-0134(00)00085-4

M3 - Article

VL - 80

SP - 219

EP - 225

JO - Journal of Inorganic Biochemistry

JF - Journal of Inorganic Biochemistry

SN - 0162-0134

IS - 3-4

ER -