Iron-Catalyzed Reductive Magnesiation of Oxetanes to Generate (3-Oxidopropyl)magnesium Reagents

Sugiyama, Yu‐ki; Heigozono, Shiori; Okamoto, Sentaro

doi:10.1021/ol503191w

Cited by 17 publications

(15 citation statements)

References 65 publications

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“…Secondary oxetanes were less reactive than tertiary oxetanes under the reaction conditions; therefore a more acidic catalyst, PMA (phosphomolybdic acid), was required. 508 In 2014, Okamoto and co-workers 509 reported the ring opening of 2-substituted oxetanes by Fe-catalyzed reductive magnesiation at the 2-position to afford substituted 3oxidopropylmagnesium compounds such as 340 in excellent yields. 2-Phenyloxetane was treated with a Grignard reagent in THF in the presence of FeCl 3 to form the ring-opened product 341 in 54% yield after workup, and this yield was increased to 99% by addition of a phosphine ligand (Scheme 134).…”

Section: Ring-opening Reactions Of Oxetanesmentioning

confidence: 99%

“…The 3-oxidopropylmagnesium intermediates 342 were also successfully quenched with electrophiles (Table 26). Okamoto and co-workers 509 proposed that the reaction proceeded via a radical mechanism, involving a low-valent Fe species. This proposal was supported by the loss of stereochemical information when diastereomeric pairs of oxetanes were used.…”

Section: Ring-opening Reactions Of Oxetanesmentioning

confidence: 99%

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Oxetanes: Recent Advances in Synthesis, Reactivity, and Medicinal Chemistry

et al. 2016

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The four-membered oxetane ring has been increasingly exploited for its contrasting behaviors: its influence on physicochemical properties as a stable motif in medicinal chemistry and its propensity to undergo ring-opening reactions as a synthetic intermediate. These applications have driven numerous studies into the synthesis of new oxetane derivatives. This review takes an overview of the literature for the synthesis of oxetane derivatives, concentrating on advances in the last five years up to the end of 2015. These methods are clustered by strategies for preparation of the ring and further derivatization of preformed oxetane-containing building blocks. Examples of the use of oxetanes in medicinal chemistry are reported, including a collation of oxetane derivatives appearing in recent patents for medicinal chemistry applications. Finally, examples of oxetane derivatives in ring-opening and ring-expansion reactions are described.

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Section: Ring-opening Reactions Of Oxetanesmentioning

confidence: 99%

Section: Ring-opening Reactions Of Oxetanesmentioning

confidence: 99%

Oxetanes: Recent Advances in Synthesis, Reactivity, and Medicinal Chemistry

et al. 2016

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“…Iron-catalyzed reductive cleavageo fa ryl and alkyl ethersb y Jacobi von Wangelinetal. [73] The resulting (3-oxidopropyl)magnesium reagents were trapped with an array of electrophiles. Iron-catalyzed cross-coupling of conjugated epoxides with alkyl and aryl Grignard reagents by Urabe et al [72] ChemSusChem 2017, 10,3964 -3981 www.chemsuschem.org (dipimp; 4mol %), and nPrMgCl (2.2 equiv) in THF at 50-60 8C (Scheme 41).…”

Section: Miscellaneous Examplesmentioning

confidence: 99%

“…Iron-catalyzed cross-coupling of conjugated epoxides with alkyl and aryl Grignard reagents by Urabe et al [72] ChemSusChem 2017, 10,3964 -3981 www.chemsuschem.org (dipimp; 4mol %), and nPrMgCl (2.2 equiv) in THF at 50-60 8C (Scheme 41). [73] The resulting (3-oxidopropyl)magnesium reagents were trapped with an array of electrophiles. Coordination of al ow-valent iron speciest ot he oxetane oxygen and strain of the four-memberedr ing drive opening through aS ET mechanism.…”

Section: Miscellaneous Examplesmentioning

confidence: 99%

Iron‐Catalyzed C−O Bond Activation: Opportunity for Sustainable Catalysis

2017

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Oxygen-based electrophiles have emerged as some of the most valuable cross-coupling partners in organic synthesis due to several major strategic and environmental benefits, such as abundance and potential to avoid toxic halide waste. In this context, iron-catalyzed C-O activation/cross-coupling holds particular promise to achieve sustainable catalytic protocols due to its natural abundance, inherent low toxicity, and excellent economic and ecological profile. Recently, tremendous progress has been achieved in the development of new methods for functional-group-tolerant iron-catalyzed cross-coupling reactions by selective C-O cleavage. These methods establish highly attractive alternatives to traditional cross-coupling reactions by using halides as electrophilic partners. In particular, new easily accessible oxygen-based electrophiles have emerged as substrates in iron-catalyzed cross-coupling reactions, which significantly broaden the scope of this catalysis platform. New mechanistic manifolds involving iron catalysis have been established; thus opening up vistas for the development of a wide range of unprecedented reactions. The synthetic potential of this sustainable mode of reactivity has been highlighted by the development of new strategies in the construction of complex motifs, including in target synthesis. The most recent advances in sustainable iron-catalyzed cross-coupling of C-O-based electrophiles are reviewed, with a focus on both mechanistic aspects and synthetic utility. It should be noted that this catalytic manifold provides access to motifs that are often not easily available by other methods, such as the assembly of stereodefined dienes or C(sp )-C(sp ) cross-couplings, thus emphasizing the synthetic importance of this mode of reactivity.

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“…[12] On the other hand, 2,2-disubstituted oxetanes are more reactive than the 3-substituted ones because of their facile ring-opening.H owever,t hey are also more sensitive to hydrolysis and polymerization. Them ain reactivity of 2,2disubstituted oxetanes include reductive ring-opening by either titanium [13] or iron [14] complexes,r ing expansion [15] to five-membered cyclic ethers,a nd perhydrolysis [16] (Figure 1). Theo xetanes have also been used as lithiation directing groups on aromatic rings.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Regioselective Isomerization of 2,2‐Disubstituted Oxetanes to Homoallylic Alcohols

et al. 2020

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The selective isomerization of strained heterocyclic compounds is an important tool in organic synthesis.A n unprecedented regioselective isomerization of 2,2-disubstituted oxetanes into homoallylic alcohols is described. The use of tris(pentafluorophenyl)borane (B(C 6 F 5 ) 3 ) , ac ommercially available Lewis acid was key to obtaining good yields and selectivities since other Lewis acids afforded mixtures of isomers and substantial polymerization. The reaction took place under exceptionally mild reaction conditions and very low catalyst loading (0.5 mol %). DFT calculations disclose the mechanistic features of the isomerization and account for the high selectivity displayed by the B(C 6 F 5 ) 3 catalyst. The synthetic applicability of the new reaction is demonstrated by the preparation of g-chiral alcohols using iridium-catalyzed asymmetric hydrogenation. Dr.A .C abrØ,S.R afael, Prof. X. Verdaguer,P rof. A. Riera Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

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Iron-Catalyzed Reductive Magnesiation of Oxetanes to Generate (3-Oxidopropyl)magnesium Reagents

Cited by 17 publications

References 65 publications

Oxetanes: Recent Advances in Synthesis, Reactivity, and Medicinal Chemistry

Oxetanes: Recent Advances in Synthesis, Reactivity, and Medicinal Chemistry

Iron‐Catalyzed C−O Bond Activation: Opportunity for Sustainable Catalysis

Catalytic Regioselective Isomerization of 2,2‐Disubstituted Oxetanes to Homoallylic Alcohols

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