Transient directing group enabled Pd-catalyzed C–H oxygenation of benzaldehydes and benzylic amines

Tian, Mixiang; Shao, Li; Su, Xiaohong; Zhou, Xuhong; Zhang, Honglei; Sun, Ruili; Wang, Junliang

doi:10.1039/d2ra00241h

Cited by 4 publications

(4 citation statements)

References 76 publications

(16 reference statements)

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“…For instance, in 2021, Wang's group developed a palladium‐catalyzed fluoroalkoxylation reaction of benzaldehydes 1 using valine to form the TDG and different fluorinated alcohols as ether provider (Scheme 2.a) [10] . Similar conditions were recently proposed but this time with an amino‐amide as TDG precursor [11] . Another palladium‐catalyzed oxygenation reaction was described by Zhang's group specifically on 1‐naphthaldehydes (Scheme 2.b) [12] .…”

Section: C(sp2)−h Functionalizationmentioning

confidence: 62%

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C−H Functionalization of Aldehydes and Ketones with Transient Directing Groups: Recent Developments

2023

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In order to directly functionalize C−H bonds of complex molecules and, in particular, to control the regioselectivity of the reaction, a wide range of directing groups has been used. However, these directing groups need to be installed and removed for further applications, which may limit the use of C−H activation in synthesis. Concerning aldehydes and ketones, a transient directing group strategy has recently emerged to overcome this drawback. The addition of an additive, in general an amine, allowed the in situ formation of the real directing group to achieve C−H activation. This review presents the latest developments in the field over the period 2020–2023.

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Section: C(sp2)−h Functionalizationmentioning

confidence: 62%

“…[10] Similar conditions were recently proposed but this time with an amino-amide as TDG precursor. [11] Another palladium-catalyzed oxygenation reaction was described by Zhang's group specifically on 1-naphthaldehydes (Scheme 2.b). [12] They were able to switch the regioselectivity of the reaction in function of the imine intermediate.…”

Section: 1a Aldehydesmentioning

confidence: 99%

C−H Functionalization of Aldehydes and Ketones with Transient Directing Groups: Recent Developments

2023

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“…Finally, after hydrolysis of 48', the expected product 48 is afforded together with the organocatalyst. Then, the group of Sun and Wang used a similar approach for the 2,2,2-trifluoroethoxylation of benzaldehydes under palladium catalysis using the amino acid 51 as organic catalyst in the presence of the fluoropyridinium salt 52 (19 examples, up to 88% yield, Scheme 23) [183]. Pleasingly, the methodology was extended to the formation of C(sp 2 )-OR F bonds starting from benzaldehyde (OR F = 2,2-difluoroethoxy 50g, 2,2-difluoropropoxy 50h, and 1,1,1,3,3,3-hexafluoroisopropoxy 50i).…”

Section: Palladium Catalysismentioning

confidence: 99%

“…Scheme 23: Pd(II)-catalyzed selective ortho-2,2,2-trifluoroethoxylation (and other fluoroalkoxylations) of benzaldehyde derivatives via the assistance of a transient directing group reported by the group of Sun and Wang[183].…”

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confidence: 99%

Transition-metal-catalyzed C–H bond activation as a sustainable strategy for the synthesis of fluorinated molecules: an overview

Monsigny¹,

Doche²,

Besset³

2023

Beilstein J. Org. Chem.

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The last decade has witnessed the emergence of innovative synthetic tools for the synthesis of fluorinated molecules. Among these approaches, the transition-metal-catalyzed functionalization of various scaffolds with a panel of fluorinated groups (XRF, X = S, Se, O) offered straightforward access to high value-added compounds. This review will highlight the main advances made in the field with the transition-metal-catalyzed functionalization of C(sp2) and C(sp3) centers with SCF3, SeCF3, or OCH2CF3 groups among others, by C–H bond activation. The scope and limitations of these transformations are discussed in this review.

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Palladium‐Catalyzed Regioselective C(4)−H Fluoroalkoxylation of Indoles Through Weak Chelation Assistance

Vijaykumar,

Gonnade,

Punji

2024

ChemCatChem

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Installing fluoroalkyl motifs into biorelevent indoles is particularly interesting due to their ubiquitous presence in drug molecules. Herein, we demonstrate the regioselective C4 fluoroalkoxylation of indoles using fluoroalcohols via palladium‐catalyzed chelation‐assisted C–H activation. The weak chelating benzoyl moiety at the C3 position acts as a directing group for remote C(4)–H fluoroalkoxylation of diversely substituted indoles. This methodology demonstrates a high level of regioselectivity and tolerates a range of crucial functional groups, yielding diverse trifluoroalkoxylated indoles in moderate to good yields. Removal of directing/protecting groups and further functionalization established the synthetic utility of the methodology. A preliminary mechanistic investigation is conducted by isolating the palladacycle intermediate and performing the deuterium scrambling study.

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Transient directing group enabled Pd-catalyzed C–H oxygenation of benzaldehydes and benzylic amines

Abstract: A general protocol for ortho-C–H fluoroalkoxylation of benzaldehydes and benzylic amines was exploited by utilizing an inexpensive amino amide as a transient directing group.

Cited by 4 publications

References 76 publications

C−H Functionalization of Aldehydes and Ketones with Transient Directing Groups: Recent Developments

C−H Functionalization of Aldehydes and Ketones with Transient Directing Groups: Recent Developments

Transition-metal-catalyzed C–H bond activation as a sustainable strategy for the synthesis of fluorinated molecules: an overview

Palladium‐Catalyzed Regioselective C(4)−H Fluoroalkoxylation of Indoles Through Weak Chelation Assistance

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