Transition‐Metal‐Catalyzed Directed C−H Functionalization in/on Water

Shah, Tariq A.; Sarkar, Tanumay; Kar, Subhradeep; Maharana, Prabhat Kumar; Talukdar, Kangkan; Punniyamurthy, Tharmalingam

doi:10.1002/asia.202300815

Cited by 3 publications

(1 citation statement)

References 158 publications

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“…In this regime, the noble metal complexes of Pd, Ru, Rh, and Ir have been extensively fostered for regioselective C–H functionalization and subsequent annulations en route to carbon–carbon and carbon-heterobond formation . To accomplish the site-selective functionalization on 4-quinolone nucleus using pyrimidine as a directing auxiliary, Hong and co-workers reported a selective C–2 alkenylation and arylation via decarbonylative cross-coupling methodology, employing the [Rh(CO) 2 Cl] 2 /( t -BuCO) 2 O catalytic system . In another exemplary work, the same group disclosed a compelling Rh(III) and Ru(II) catalyzed regioselective C5 and C2 alkynylation using ethynylbenzoiodoxolone (TIPS-EBX) reagent .…”

Section: Introductionmentioning

confidence: 99%

Palladium-Catalyzed, Site-Selective C(sp²)8–H Halogenation and Nitration of 4-Quinolone Derivatives

Das,

Ghosh,

Ghosh

et al. 2024

J. Org. Chem.

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Selective installation of halo and nitro groups in heterocyclic backbone through a transition-metal-catalyzed C−H bond activation strategy is immensely alluring to access high-value scaffolds. Here in, we disclosed N-pyrimidyl-directed assisted palladium(II)-catalyzed C(sp 2 )8−H halogenation and nitration of substituted 4-quinolone derivatives in the presence of Nhalosuccinimide and tert-butyl nitrite, respectively, offering structurally diversified 8-halo/nitro-embedded 4-quinolone frameworks in high yields. Mechanistic studies indicated that the reaction follows an organometallic pathway with a reversible C−H metalation step. This operationally simple protocol is scalable with a broad substrate scope and excellent functional group compatibility. Moreover, the postdiversifications of the synthesized derivatives are also showcased to ensure the synthetic versatility of the methodology.

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Section: Introductionmentioning

confidence: 99%

Palladium-Catalyzed, Site-Selective C(sp²)8–H Halogenation and Nitration of 4-Quinolone Derivatives

Das,

Ghosh,

Ghosh

et al. 2024

J. Org. Chem.

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Construction of C5‐Indole Unnatural Amino Acid Motifs via Diastereoselective Pd(II)‐Catalyzed β‐C(sp³)‐H Functionalization

Patel,

Babu,

Tomar

2024

Eur J Org Chem

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We report the construction of C5‐indole unnatural amino acid derivatives via the diastereoselective Pd(II)‐catalyzed prochiral β‐C(sp3)‐H arylation of racemic (DL), and enantiopure L‐ and D‐carboxamides of amino acids with 5‐iodoindoles. Independently, indole‐based compounds and amino acid motifs are important small molecules in organic synthesis and drug discovery research. This report aimed to contribute to enriching the library of indole‐based unnatural amino acid derivatives. The synthesis of examples of C5‐indole motif‐installed amino acid derivatives comprising norvaline, phenylalanine, leucine, norleucine, 2‐aminooctanoic acid having anti‐stereochemistry was accomplished. The synthesis of the C5‐indole motif‐containing non‐α‐amino acid (aminoalkanoic acid) derivatives was also reported. The C‐H arylation reactions of racemic and enantiopure carboxamides with 5‐iodoindoles afforded the corresponding indole unnatural amino acid derivatives with good diastereoselectivity (anti, dr >95:5 and enantiopurity (er up to 99:1). Removal of the directing group (8‐aminoquinoline), phthalimide group and preparation of indole amino acid esters and free amino group‐containing indole unnatural amino acid motifs were also shown. The utility of the methodology was shown by synthesizing indole motif‐containing pyrrolidone and peptide molecules. The stereochemistry of the major (anti) diastereomers was ascertained from the X‐ray structure of a representative compound.

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Fluorene and Fluorenone Unnatural Amino Acid Motifs via Diastereoselective Pd(II)‐Catalyzed sp³C−H Functionalization

Banga,

Babu

2024

Eur J Org Chem

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This paper reports the construction of racemic and enantiopure (D‐ and L‐) fluorene and fluorenone‐based novel unnatural amino acid derivatives. The Pd(II)‐catalyzed bidentate directing group‐aided arylation of prochiral β‐C(sp3)‐H bonds in racemic, enantiopure carboxamides of amino acids with iodofluorenes was reported. The construction of novel examples of fluorene and fluorenone motifs containing amino acids comprising of norvaline, leucine, phenylalanine, norleucine, 2‐aminooctanoic acid derivatives having the anti‐stereochemistry (with good enantiopurity) was accomplished. The construction of bis fluorenyl alanine scaffolds and fluorenyl motif‐containing non‐α‐amino acid (aminoalkanoic acid) derivatives was also reported. Examples of removal of the directing group (8‐aminoquinoline) and phthalimide‐protecting group present in the fluorenyl‐based unnatural amino acid derivatives have been shown. Accordingly, fluorene motif‐based amino acid esters and free amino group‐containing unnatural amino acid derivatives were synthesized. The stereochemistry of the major (anti) diastereomers obtained via the prochiral β‐C(sp3)‐H arylation of norvaline, leucine, phenylalanine, norleucine, 2‐aminooctanoic acid derivatives was ascertained from the X‐ray structure of a representative compound. Fluorene‐ and fluorenone‐based motifs are vital skeletons in materials and medicinal chemistry research. Accordingly, this work is a contribution towards enriching the library of fluorene and fluorenone unnatural amino acid scaffolds.

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Transition‐Metal‐Catalyzed Directed C−H Functionalization in/on Water

Cited by 3 publications

References 158 publications

Palladium-Catalyzed, Site-Selective C(sp²)8–H Halogenation and Nitration of 4-Quinolone Derivatives

Palladium-Catalyzed, Site-Selective C(sp²)8–H Halogenation and Nitration of 4-Quinolone Derivatives

Construction of C5‐Indole Unnatural Amino Acid Motifs via Diastereoselective Pd(II)‐Catalyzed β‐C(sp³)‐H Functionalization

Fluorene and Fluorenone Unnatural Amino Acid Motifs via Diastereoselective Pd(II)‐Catalyzed sp³C−H Functionalization

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Transition‐Metal‐Catalyzed Directed C−H Functionalization in/on Water

Cited by 3 publications

References 158 publications

Palladium-Catalyzed, Site-Selective C(sp2)8–H Halogenation and Nitration of 4-Quinolone Derivatives

Palladium-Catalyzed, Site-Selective C(sp2)8–H Halogenation and Nitration of 4-Quinolone Derivatives

Construction of C5‐Indole Unnatural Amino Acid Motifs via Diastereoselective Pd(II)‐Catalyzed β‐C(sp3)‐H Functionalization

Fluorene and Fluorenone Unnatural Amino Acid Motifs via Diastereoselective Pd(II)‐Catalyzed sp3C−H Functionalization

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Palladium-Catalyzed, Site-Selective C(sp²)8–H Halogenation and Nitration of 4-Quinolone Derivatives

Palladium-Catalyzed, Site-Selective C(sp²)8–H Halogenation and Nitration of 4-Quinolone Derivatives

Construction of C5‐Indole Unnatural Amino Acid Motifs via Diastereoselective Pd(II)‐Catalyzed β‐C(sp³)‐H Functionalization

Fluorene and Fluorenone Unnatural Amino Acid Motifs via Diastereoselective Pd(II)‐Catalyzed sp³C−H Functionalization