The Choice of Rhodium Catalysts in [2+2+2] Cycloaddition Reaction: A Personal Account

Pla‐Quintana, Anna; Roglans, Anna

doi:10.3390/molecules27041332

Cited by 11 publications

(2 citation statements)

References 47 publications

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“…Under inert atmosphere at room temperature with freshly clean glassware in deuterated chloroform (CDCl3), we treated fluor[9+1]CPP with a metal catalyst (approximately 20% catalyst loading) for one hour and assessed the results of each reaction with quantitative 19 F NMR (Table 1 and Scheme 1). The screened metals are well-known catalysts for alkyne trimerization; Rh(I) 32,33 and Ni(0) [34][35][36] are common catalysts for the trimerization of unstrained alkynes, while Pd(0) [37][38][39] is often an effective catalyst for aryne trimerization.…”

Section: Resultsmentioning

confidence: 99%

Pinwheel-like Curved Aromatics from the Cyclotrimerization of Strained Alkyne Cycloparaphenylenes

Fehr,

Clayton,

Price

et al. 2024

Preprint

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Curved aromatic hydrocarbons often display better solubility and more desirable electronic properties in comparison to their flat counterparts. Macrocyclic curved aromatics possess these traits as well as shape-persistent pores ideal for host-guest interactions. A quintessential macrocyclic curved aromatic molecule is the cycloparaphenylene, or [n]CPP. Our group has developed a new class of these carbon nanohoops, called [n+1]CPPs, that incorporate a strained alkyne (“+1”) into the carbon backbone. We have previously shown the [n+1]CPPs to be a promising new class of strain-promoted azide-alkyne cycloaddition click reagents. Herein, we show that the [n+1]CPPs can also be converted into pinwheel-like multi-pore large molecules via a straightforward and high yielding metal-mediated alkyne cyclotrimerization reaction. We provide insight into suitable metals for this transformation, the photophysics of these trimeric molecules, as well as their strain profiles and crystal packing.

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Section: Resultsmentioning

confidence: 99%

Pinwheel-like Curved Aromatics from the Cyclotrimerization of Strained Alkyne Cycloparaphenylenes

Fehr,

Clayton,

Price

et al. 2024

Preprint

View full text Add to dashboard Cite

show abstract

“…In 2019, our group utilized this strategy for the synthesis of a highly strained prismatic [2.2.2] carbon nanocage via the cationic Rh I ‐catalyzed [2+2+2] cycloaddition of an L‐shaped cyclohexadienylacetylene derivative followed by cross‐coupling and reductive aromatization (Figure 1b). [23] In this synthesis, the bulkiness of this terminal alkyne and the high catalytic activity of the cationic Rh I complex [24, 25] made the [2+2+2] cycloaddition excellent 1,3,5‐selectivity and good yield, respectively. However, the subsequent cross‐coupling and reductive aromatization both proceed in low yield.…”

Section: Introductionmentioning

confidence: 99%

Shape‐ and Size‐Tunable Synthesis of Covalent Organic Cages through Rh‐Catalyzed Regioselective [2+2+2] Cycloaddition

et al. 2023

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Covalent organic cages have potential applications in molecular inclusion/recognition and porous organic crystals. Bridging arene units with sp 3 atoms enables facile construction of rigid isolated internal vacancies, and various prismatic arene cages have been synthesized by kinetically controlled covalent bond formation. However, the synthesis of a tetrahedral one, which requires twice as much bond formation as prismatic ones, has been limited to a thermodynamically controlled dynamic S N Ar reaction, and this reversible covalent bond formation made the resulting cage product chemically unstable. Here we report the Rhcatalyzed high-yielding and highly 1,3,5-selective room temperature [2+2+2] cycloaddition of push-pull alkynes and its application to the synthesis of chemically stable aryl ether cages of various shapes and sizes, including prismatic and tetrahedral forms. These aryl ether cages are highly crystalline and intertwine with each other to form regular packing structures. Some aryl ether cages encapsulated isolated water molecules in their hydrophobic cavity by hydrogen bonding with the multiple ester moieties.

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Rhodium‐Catalyzed Chemo‐, Regio‐, Diastereo‐, and Enantioselective Intermolecular [2+2+2] Cycloaddition of Three Unsymmetric 2π Components

et al. 2023

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We have developed the Rh + /H 8 -binap-catalyzed chemo-, regio-, diastereo-, and enantioselective intermolecular [2+2+2] cycloaddition of three unsymmetric 2π components. Thus, two arylacetylenes react with a cis-enamide to yield a protected chiral cyclohexadienylamine. Moreover, replacing one arylacetylene with a silylacetylene enables the [2+2+2] cycloaddition of three distinct unsymmetric 2π components. These transformations proceed with excellent selectivity (complete regio-and diastereoselectivity and up to > 99 % yield and > 99 % ee). Mechanistic studies suggest the chemo-and regioselective formation of a rhodacyclopentadiene intermediate from the two terminal alkynes.

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The Choice of Rhodium Catalysts in [2+2+2] Cycloaddition Reaction: A Personal Account

Cited by 11 publications

References 47 publications

Pinwheel-like Curved Aromatics from the Cyclotrimerization of Strained Alkyne Cycloparaphenylenes

Pinwheel-like Curved Aromatics from the Cyclotrimerization of Strained Alkyne Cycloparaphenylenes

Shape‐ and Size‐Tunable Synthesis of Covalent Organic Cages through Rh‐Catalyzed Regioselective [2+2+2] Cycloaddition

Rhodium‐Catalyzed Chemo‐, Regio‐, Diastereo‐, and Enantioselective Intermolecular [2+2+2] Cycloaddition of Three Unsymmetric 2π Components

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