Metalloradical Catalysis: General Approach for Controlling Reactivity and Selectivity of Homolytic Radical Reactions

Angewandte Chemie, Journal Year: 2024, Volume and Issue: 136(20)

Published: March 13, 2024

Abstract Since Friedrich Wöhler's groundbreaking synthesis of urea in 1828, organic over the past two centuries has predominantly relied on exploration and utilization chemical reactions rooted two‐electron heterolytic ionic chemistry. While one‐electron homolytic radical chemistry is both rich fundamental reactivities attractive with practical advantages, synthetic application been long hampered by formidable challenges associated control reactivity selectivity high‐energy intermediates. To fully harness untapped potential for synthesis, there a pressing need to formulate radically different concepts broadly applicable strategies address these outstanding issues. In pursuit this objective, researchers have actively developing metalloradical catalysis (MRC) as comprehensive framework guide design general approaches controlling stereoselectivity reactions. Essentially, MRC exploits metal‐centered radicals present open‐shell metal complexes catalysts activation substrates generate metal‐entangled key intermediates govern reaction pathway stereochemical course subsequent catalytic processes. Different from conventional transition complexes, operates through utilizing stepwise mechanisms.

Language: Английский

---

Light Induced Cobalt(III) Carbene Radical Formation from Dime-thyl Malonate as Carbene Precursor

Published: April 3, 2024

Radical-type carbene transfer catalysis is an efficient method for the direct functionalization of C–H and C=C bonds. However, radical complexes are currently formed via high-energy precursors, such as diazo compounds or iodonium ylides. Many these precursors require additional synthetic steps, have explosive nature generate halogenated waste. Con-sequently, utilization limited by specific to access inter-mediate. In this study, we a cobalt(III) complex from dimethyl malonate, which commercially available bench-stable. EPR NMR spectroscopy were used identify intermediates showed that upon light irradiation. presence styrene, occurred, forming cyclopropane product. With photochemical method, demonstrate malonate can be alternative precursor in formation complex.

Language: Английский

---

Copper(I)-Catalyzed Indolyl Ynamide Oxidation/Dearomatization: Divergent and Regioselective Synthesis of Valuable Indoline Scaffolds

Organic Letters, Journal Year: 2024, Volume and Issue: 26(18), P. 3715 - 3721

Published: April 28, 2024

A highly convenient copper(I)-catalyzed oxidation-initiated cyclopropanation of indolyl ynamide for the rapid construction indole-fused cyclopropane-lactams is described, which represents, to best our knowledge, first non-noble-metal-catalyzed oxidation/dearomatization by in situ generated α-oxo copper carbenes. Compared hydrazone and diazo, use alkynes as carbene precursors allows occur under a safe pathway. Moreover, this transformation can lead divergent synthesis pentacyclic spiroindolines involving reversal regioselectivity engineering substrate structures.

Language: Английский

---

Cobalt‐Catalyzed Enantioselective Reductive α‐Chloro‐Carbonyl Addition of Ketimine to Construct the β‐Tertiary Amino Acid Analogues

Angewandte Chemie, Journal Year: 2024, Volume and Issue: 136(25)

Published: Jan. 22, 2024

Abstract β‐Tertiary amino acid derivatives constitute one of the most frequently occurring units in natural products and bioactive molecules. However, efficient asymmetric synthesis this motif still remains a significant challenge. Herein, we disclose cobalt‐catalyzed enantioselective reductive addition reaction ketimine using α‐chloro carbonyl compound as radical precursor, providing expedient access to diverse array enantioenriched β‐quaternary analogues. This protocol exhibits outstanding enantioselectivity broad substrate scope with excellent functional group tolerance. Preliminary mechanism studies rule out possibility Reformatsky‐type confirm involvement species stereoselective process. The synthetic utility has been demonstrated through rapid assembly iterative oligopeptide, showcasing its versatile platform for late‐stage modification drug candidates.

Language: Английский

---

Stepwise Carbene Transfer Reaction with Alkenes beyond Cyclopropanation

Synthesis, Journal Year: 2024, Volume and Issue: 56(18), P. 2886 - 2898

Published: April 9, 2024

Abstract Metal carbene transfer reactions have been well-established as an indispensable tool in modern organic synthesis, especially the construction of C–C and C–X bonds with high efficiency selectivity. Among these, stepwise reaction alkenes beyond classical cyclopropanation has demonstrated a practical method for effective olefinic C–H/C–C bond functionalization. This review highlights recent achievements this area direct formation involving metal species through pathway. The content is organized into three general categories according to types reactions, including (i) nucleophilic addition species, (ii) cross-coupling via alkenylic C–H activation migration insertion sequence, (iii) catalytic coupling radical intermediate. Considering rapidly evolving field, detailed mechanism, current limitations, future research directions are discussed. 1 Introduction 2 Nucleophilic Addition Alkenes Carbene Species 2.1 Using Polarized 2.2 Unactivated 2.3 Cascade Reactions 3 Cross-Coupling Reaction Involving Migratory Insertion Process 4 Coupling Radical Intermediate 5 Conclusions Perspectives

Language: Английский

---

Single catalyst double outer-sphere alkene cross-coupling

Published: Nov. 17, 2023

Cross-coupling catalysts typically react and unite functionally distinct partners via sequential inner-sphere elementary steps: coordination, migratory insertion, reductive elimination, etc. Here we report a single catalyst that cross-couples styrenes benzyl bromides iterative outer-sphere metal-ligand-carbon interactions. Each partner forms stabilized radical in-termediate yet hetero-coupled products predominate. The system is redox neutral thus avoids exogenous oxidant, resulting in simple scalable conditions. Numerous variations of alkene hydrobenzylation are made possible, including access to the privileged hetero-dibenzyl (1,2-diarylethane) motif challenging quaternary carbon variants.

Language: Английский

---

Design and Synthesis of C₄‐Symmetric Axially Chiral β‐Aryl Porphyrins and Application for Supporting Ir(III)‐Catalyzed Enantioselective C−H Alkylation

Angewandte Chemie, Journal Year: 2024, Volume and Issue: 136(28)

Published: April 29, 2024

Abstract A hitherto unknown class of C 4 ‐symmetric aryl −C β (C 3 , 8 13 18 ) axially chiral porphyrins has been synthesized and the application their iridium (Ir) complexes in catalytic asymmetric C(sp )−H functionalization is documented. Cyclotetramerization enantioenriched 2‐hydroxymethyl‐3‐naphthyl pyrroles under mild acidic conditions affords, after oxidation with 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ), α,α,α,α‐atropenantiomer as an only isolable diastereomer. Both regioisomeric Ir(Por*)(CO)(Cl) catalyze carbene C−H insertion reaction affording same enantiomer, albeit slight difference enantioselectivity. With optimum Ir‐complex e 2‐substituted arylacetic acid derivatives were generated from diazo compounds cyclohexadiene excellent yields enantioselectivities.

Language: Английский

---

Light Induced Cobalt(III) Carbene Radical Formation from Dimethyl Malonate As Carbene Precursor

Organometallics, Journal Year: 2024, Volume and Issue: 43(11), P. 1299 - 1307

Published: May 24, 2024

Radical-type carbene transfer catalysis is an efficient method for the direct functionalization of C–H and C═C bonds. However, radical complexes are currently formed via high-energy precursors, such as diazo compounds or iodonium ylides. Many these precursors require additional synthetic steps, have explosive nature, generate halogenated waste. Consequently, utilization limited by specific that access intermediate. In this study, we a cobalt(III) complex from dimethyl malonate, which commercially available bench-stable. EPR NMR spectroscopy were used to identify intermediates showed upon light irradiation. presence styrene, occurred, forming cyclopropane product. With photochemical method, demonstrate malonate can be alternative precursor in formation complex.

Language: Английский

---

Iron(II) Phthalocyanine-Catalyzed Homodimerization and Tandem Diamination of Diazo Compounds with Primary Amines: Access to Construct Substituted 2,3-Diaminosuccinonitriles in One-Pot

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 89(11), P. 7718 - 7726

Published: May 24, 2024

We herein first report the homodimerization and tandem diamination of diazo compounds with primary amines catalyzed by iron(II) phthalocyanine (PcFe(II)), which can construct one C-C bond two C-N bonds within 20 min in one-pot. Compared to traditional metal-catalyzed N-H insertion reaction between reagents, developed almost does not generate product, but homodimerization/tandem product. The proposed mechanism studies indicate that play a crucial role homocoupling via dimerization iron(III)-acetonitrile radical generated from diazoacetonitrile PcFe(II) coordinated bis(amines); β-hydride elimination is involved, then, attack toward carbon atoms on formed followed. Moreover, this novel be used effectively prepare substituted 2,3-diaminosuccinonitriles high yields even up >99:1 d.r., encouragingly these products contain both 1,2-diamines succinonitrile motifs, are classes important organic significant applications many yields. This also suitable for gram-scale preparation 2,3-bis(phenylamino)succinonitrile (

Language: Английский

---

Chiral metal complexes: Design strategies for precision in asymmetric C–H activation

Journal of Catalysis, Journal Year: 2024, Volume and Issue: unknown, P. 115756 - 115756

Published: Sept. 1, 2024

Language: Английский

---