Iron‐Catalyzed Stereoselective Cross‐Coupling Reactions of Stereodefined Enol Carbamates with Grignard Reagents

Rivera, Ana Cristina Parra; Still, Raymond; Frantz, Doug E.

doi:10.1002/ange.201601899

Cited by 15 publications

(5 citation statements)

References 50 publications

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“…In 2016, the group of Frantz reported an efficient preparation of stereodefined tri-and tetrasubstituted olefins by selective iron-catalyzed cross-coupling of enol carbamates with alkyl Grignard reagents (Scheme1 1). [32] As eries of (E)-and (Z)enol carbamates, prepared by am odification of the method previously developedb yt he authors, [33] underwent cross-coupling in the presenceo fc atalytic FeCl 3 (5 mol %) in THF/NMP at À78 to À40 8C. This system was found to be generalf or cross-coupling, affording the products with excellent stereoselectivity for both E and Z substrates (typically > 20:1).…”

Section: Cross-coupling Of Sulfamates Carbamates and Carboxylatesmentioning

confidence: 98%

“…Scheme11. Iron-catalyzed cross-coupling of enol carbamates with alkyl Grignard reagents by Frantz et al [32] Scheme12. Iron-catalyzed cross-coupling of 2-pyrones with alkyl Grignard reagents by Fürstner et al [34] of awide range of natural products.…”

Section: Cross-coupling Of Sulfamates Carbamates and Carboxylatesmentioning

confidence: 99%

“…[41] The methodu ses ac atalytic systemb ased on FeCl 3 (5 mol %) or [Fe(dmb) 3 ]( 5mol %) in THF at 0-5 8Ci nt he absence of additional ligands. Synthetically,t his transformation is reminiscent of the methodr eported by Frantz et al for the cross-coupling of stereodefined enol carbamates (see Scheme 11), [32] and relies on the efficient preparation of stereodefined enol tosylates precursors, as reported earlier by the same authors. [42] The cross-coupling proceeds with high levelso fs electivity fora lkyl Scheme13.…”

Section: Cross-coupling Of Sulfonates and Phosphatesmentioning

confidence: 99%

“…[32] As eries of (E)-and (Z)enol carbamates, prepared by am odification of the method previously developedb yt he authors, [33] underwent cross-coupling in the presenceo fc atalytic FeCl 3 (5 mol %) in THF/NMP at À78 to À40 8C. [32] As eries of (E)-and (Z)enol carbamates, prepared by am odification of the method previously developedb yt he authors, [33] underwent cross-coupling in the presenceo fc atalytic FeCl 3 (5 mol %) in THF/NMP at À78 to À40 8C.…”

Section: Introduction and Early Studiesmentioning

confidence: 99%

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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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Section: Cross-coupling Of Sulfamates Carbamates and Carboxylatesmentioning

confidence: 98%

Section: Cross-coupling Of Sulfamates Carbamates and Carboxylatesmentioning

confidence: 99%

Section: Cross-coupling Of Sulfonates and Phosphatesmentioning

confidence: 99%

Section: Introduction and Early Studiesmentioning

confidence: 99%

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

2017

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“…However, a vast majority of these transformations are structurally limited to α,β-unsaturated compounds, such as acrylates and ketones. [34][35][36][37][38][39][40][41][42] In contrast, highly stereoselective methods for the assembly of unactivated acyclic tetrasubstituted alkenes have remained scarce. In 2017, our group reported a two-step synthesis of tetrasubstituted alkenes, in which the stereochemical outcome is set by diastereoselective preparation of the enol tosylate starting material, followed by a stereoretentive Pd-catalyzed Suzuki-Miyaura cross-coupling (Figure 1B).…”

Section: Introductionmentioning

confidence: 99%

Stereoconvergent and -divergent Synthesis of Tetrasubstituted Alkenes by Nickel-Catalyzed Cross-Couplings

Zell¹,

Kingston

Jermaks³

et al. 2021

J. Am. Chem. Soc.

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We report the development of a method to diastereoselectively access tetrasubstituted alkenes via nickel-catalyzed Suzuki-Miyaura cross-couplings of enol tosylates and boronic acid esters. Either diastereomeric product was selectively accessed from a mixture of enol tosylate starting material diastereomers in a convergent reaction by judicious choice of the ligand and reaction conditions. A similar protocol also enabled a divergent synthesis of each product isomer from diastereomerically pure enol tosylates. Notably, high-throughput optimization of the monophosphine ligands was guided by chemical space analysis of the kraken library to ensure a diverse selection of ligands was examined. Stereoelectronic analysis of the results provided insight into the requirements for reactive and selective ligands in this transformation. The synthetic utility of the optimized catalytic system was then probed in the stereoselective synthesis of various tetrasubstituted alkenes, with yields up to 94% and diastereomeric ratios up to 99:1 Z/E and 93:7 E/Z observed. Moreover, a detailed computational analysis and experimental mechanistic studies provided key insights into the nature of the underlying isomerization process impacting selectivity in the cross-coupling. ASSOCIATED CONTENTThe Supporting Information is available free of charge at http://pubs.acs.org." Experimental procedures, characterization and spectral data for all new compounds.

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Chemoselective Kumada‐Type Iron Catalysis with Alkyl Grignard Reagents: Reductive Cyclization and Cyclomethylation

et al. 2019

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A chemoselective reductive cyclization and cyclomethylation reaction of 7‐iodohept‐2‐yne and 7‐iodohepta‐1,2‐diene derivatives has been carried out using an iron catalyst and various alkyl Grignard reagents, resulting in the formation of pyrrolidines, tetrahydrofurans, and carbocycles with an alkene functional group. The reaction is initiated by single‐electron transfer from reduced Fe species to alkyl iodides and the resulting Fe−H or Fe−Me compound differentiated the structures of the cyclized products, which exhibited diverse complexities and synthetic utilities.

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Iron‐Catalyzed Stereoselective Cross‐Coupling Reactions of Stereodefined Enol Carbamates with Grignard Reagents

Cited by 15 publications

References 50 publications

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

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

Stereoconvergent and -divergent Synthesis of Tetrasubstituted Alkenes by Nickel-Catalyzed Cross-Couplings

Chemoselective Kumada‐Type Iron Catalysis with Alkyl Grignard Reagents: Reductive Cyclization and Cyclomethylation

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