A comparative study of the asymmetric epoxidation of aromatic olefins using the first generation manganese salen epoxidation catalysts and their light fluorous variants: an interesting discovery on the use of benzotrifluoride as a cosolvent

Kobayashi, Yuki; Inukai, Sae; Asai, Naoki; Oyamada, Mami; Ikegawa, Shohei; Sugiyama, Yasumasa; Hamamoto, Hiromi; Shioiri, Takayuki; Matsugi, Masato

doi:10.1016/j.tetasy.2014.07.003

Cited by 13 publications

(8 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The obtained spectroscopic data of 2-phenyloxirane ( 2 ) [59] and 2,3-diphenyloxirane ( 9 ) [42] was in accordance with commercially available 2-phenyloxirane and data from literature.…”

Section: Methodssupporting

confidence: 64%

Biomimetic Non-Heme Iron-Catalyzed Epoxidation of Challenging Terminal Alkenes Using Aqueous H2O2 as an Environmentally Friendly Oxidant

et al. 2019

View full text Add to dashboard Cite

Catalysis mediated by iron complexes is emerging as an eco-friendly and inexpensive option in comparison to traditional metal catalysis. The epoxidation of alkenes constitutes an attractive application of iron(III) catalysis, in which terminal olefins are challenging substrates. Herein, we describe our study on the design of biomimetic non-heme ligands for the in situ generation of iron(III) complexes and their evaluation as potential catalysts in epoxidation of terminal olefins. Since it is well-known that active sites of oxidases might involve imidazole fragment of histidine, various simple imidazole derivatives (seven compounds) were initially evaluated in order to find the best reaction conditions and to develop, subsequently, more elaborated amino acid-derived peptide-like chiral ligands (10 derivatives) for enantioselective epoxidations.

show abstract

“…The obtained spectroscopic data of 2-phenyloxirane ( 2 ) [59] and 2,3-diphenyloxirane ( 9 ) [42] was in accordance with commercially available 2-phenyloxirane and data from literature.…”

Section: Methodssupporting

confidence: 64%

Biomimetic Non-Heme Iron-Catalyzed Epoxidation of Challenging Terminal Alkenes Using Aqueous H2O2 as an Environmentally Friendly Oxidant

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Through our previous study, we know that the introduction of fluorous tags to the 3′ and 5′ position on Jacobsen‐type Mn(III) salen ligands increases the oxidation activity of the catalyst for isolated double bonds . Therefore, we attempted to activate Fe(III) salen complexes by introducing fluorous tags onto the ligands…”

Section: Resultsmentioning

confidence: 99%

“…This observation is significant because currently known salen Mn(III) complexes are typically more effective for cis ‐olefins. [5c] For example, when the epoxidation of substrate 7 is conducted using a Mn(III) complex 4 under PhIO conditions, the obtained enantiomeric excess is 1 % ee . However, the fluorous Fe(III) version exhibited a stereoselectivity that exceeds 36 % ee under the same conditions (Entry 2) .…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Unprecedented Asymmetric Epoxidation of Isolated Carbon–Carbon Double Bonds by a Chiral Fluorous Fe(III) Salen Complex: Exploiting Fluorophilic Effect for Catalyst Design

et al. 2019

Self Cite

View full text Add to dashboard Cite

The first asymmetric epoxidation of isolated carbon–carbon double bonds by a chiral salen complex using ubiquitous Fe(III) as a center‐metal is described. By simultaneously introducing fluorous tags and tert‐butyl groups into the ligand of the salen complex, asymmetric epoxidation is achieved. The fluorous tags act as both the electron‐withdrawing groups, to improve the catalytic activity for oxidation, and the driving force to form a unique asymmetric stereo environment. Crystallographic analysis of the complex revealed that the catalyst has a distinctive umbrella structure based on intramolecular fluorophilic effect. This is the first example of asymmetric catalytic space construction that exploits fluorous space‐interaction of neighboring fluorous tags.

show abstract

“…iodosylbenzene (PhIO), NaOCl and H 2 O 2 . The extensive use of metal salen complexes in homogeneous catalysis can be attributed to their high activity, selectivity and enantioselectivity (when chiral complexes are used) . The easy availability of active sites of homogeneous catalysts enhances their efficiency, but their liability lies in the difficulty in their separation from reaction mixtures.…”

Section: Introductionmentioning

confidence: 99%

A route to magnetically separable nanocatalysts: Combined experimental and theoretical investigation of alkyl substituent role in ligand backbone towards epoxidation ability

Chattopadhyay

Chakraborty

Dasgupta

et al. 2016

Applied Organom Chemis

View full text Add to dashboard Cite

We have prepared two chiral Schiff base ligands, H2L1 and H2L2, and one achiral Schiff base ligand, H2L3, by treating 2,6‐diformyl‐4‐methylphenol separately with (R)‐1,2‐diaminopropane, (R)‐1,2‐diaminocyclohexane and 1,1′‐dimethylethylenediamine, in ethanolic medium, respectively. The complexes MnL1ClO4 (1), MnL2ClO4 (2), MnL3ClO4 (3), FeL1ClO4 (4), FeL2ClO4 (5) and FeL3ClO4 (6) have been obtained by reacting the ligands H2L1, H2L2 and H2L3 with manganese(III) perchlorate or iron(III) perchlorate in methanol. Circular dichroism studies suggest that ligands H2L1 and H2L2 and their corresponding complexes have asymmetric character. Complexes 1–6 have been used as homogeneous catalysts for epoxidation of alkenes. Manganese systems have been found to be much better than iron counterparts for alkene epoxidation, with 3 as the best catalyst among manganese systems and 6 as the best among iron systems. The order of their experimental catalytic efficiency has also been rationalized by theoretical calculations. We have observed higher enantiomeric excess product with catalysts 1 and 4, so they were attached to surface‐modified magnetic nanoparticles to obtain two new magnetically separable nanocatalysts, Fe3O4@dopa@MnL1 and Fe3O4@dopa@FeL4. They have been characterized and their alkene epoxidation ability has been investigated. These catalysts can be easily recovered by magnetic separation and recycled several times without significant loss of catalytic activity. Hence our study focuses on the synthesis of a magnetically recoverable asymmetric nanocatalyst that finds applications in epoxidation of alkenes and at the same time can be recycled and reused.

show abstract

A comparative study of the asymmetric epoxidation of aromatic olefins using the first generation manganese salen epoxidation catalysts and their light fluorous variants: an interesting discovery on the use of benzotrifluoride as a cosolvent

Cited by 13 publications

References 26 publications

Biomimetic Non-Heme Iron-Catalyzed Epoxidation of Challenging Terminal Alkenes Using Aqueous H2O2 as an Environmentally Friendly Oxidant

Biomimetic Non-Heme Iron-Catalyzed Epoxidation of Challenging Terminal Alkenes Using Aqueous H2O2 as an Environmentally Friendly Oxidant

Unprecedented Asymmetric Epoxidation of Isolated Carbon–Carbon Double Bonds by a Chiral Fluorous Fe(III) Salen Complex: Exploiting Fluorophilic Effect for Catalyst Design

A route to magnetically separable nanocatalysts: Combined experimental and theoretical investigation of alkyl substituent role in ligand backbone towards epoxidation ability

Contact Info

Product

Resources

About