Bis-Cyclometalated Indazole and Benzimidazole Chiral-at-Iridium Complexes: Synthesis and Asymmetric Catalysis

Brunen, Sebastian; Grell, Yvonne; Steinlandt, Philipp S.; Harms, Klaus; Meggers, Eric

doi:10.3390/molecules26071822

Cited by 12 publications

(3 citation statements)

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“…In the second iteration thirteen chiral-at-rhodium catalysts were screened in the cyclization of 7 (see page S-7†). 11 The three best catalysts were subsequently evaluated in the reactions of the more challenging fully substituted diketoesters 9 so as to determine the effect of the ester group R 1 (Table 1). The rhodium catalyst in which R = 1-adamantyl converted diketoester 9 (R 1 = Et) to product 10 in 96 : 4 er (entry 1).…”

Section: Resultsmentioning

confidence: 99%

Anion-accelerated asymmetric Nazarov cyclization: access to vicinal all-carbon quaternary stereocenters

2023

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Section: Resultsmentioning

confidence: 99%

Anion-accelerated asymmetric Nazarov cyclization: access to vicinal all-carbon quaternary stereocenters

2023

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“…While M65 remains the benchmark for chiral-at-iridium catalysis, a number of related bis-cyclometalated iridium complexes were introduced for applications in asymmetric catalysis including polymer-supported, bis-cyclometalated iridium catalysts, bis-cyclometalated NHC iridium catalysts, , and bis-cyclometalated indazole and benzimidazole chiral-at-iridium catalysts …”

Section: Stereogenic-at-metal Catalysts From Solely Achiral or Optica...mentioning

confidence: 99%

“…184 While M65 remains the benchmark for chiral-at-iridium catalysis, a number of related bis-cyclometalated iridium complexes were introduced for applications in asymmetric catalysis including polymer-supported, bis-cyclometalated iridium catalysts, 189 bis-cyclometalated NHC iridium catalysts, 190,191 and bis-cyclometalated indazole and benzimidazole chiral-at-iridium catalysts. 192 In 2015, Meggers introduced bis-cyclometalated chiral-atrhodium(III) complexes as chiral Lewis acids, some of which are displayed in Scheme 23. 193 Λand Δ-M66, which are the lighter congeners of Λand Δ-M62, contain two inert cyclometalated 5-tert-butyl-2-phenylbenzoxazoles in addition to two labile acetonitrile ligands with hexafluorophosphate serving as the counterion for the monocationic complexes.…”

Section: Hexacoordinated Chiral-at-metal Catalystsmentioning

confidence: 99%

Metal Stereogenicity in Asymmetric Transition Metal Catalysis

2023

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Chiral transition metal catalysts represent a powerful and economic tool for implementing stereocenters in organic synthesis, with the metal center providing a strong chemical activation upon its interaction with substrates or reagents, while the overall chirality of the metal complex achieves the desired stereoselectivity. Often, the overall chiral topology of the metal complex implements a stereogenic metal center, which is then involved in the origin of the asymmetric induction. This review provides a comprehensive survey of reported chiral transition metal catalysts in which the metal formally constitutes a stereocenter. A stereogenic metal center goes along with an overall chiral topology of the metal complex, regardless of whether the ligands are chiral or achiral. Implications for the catalyst design and mechanism of asymmetric induction are discussed for half-sandwich, tetracoordinated, pentacoordinated, and hexacoordinated chiral transition metal complexes containing a stereogenic metal center. The review distinguishes between chiral metal catalysts originating from the coordination to chiral ligands and those which are solely composed of optically inactive ligands (achiral or rapidly interconverting enantiomers) prior to complexation (dubbed “chiral-at-metal” catalysts).

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Advancement in Heterogeneous Catalysts for the Synthesis of Benzothiazole Derivatives

Kohli,

Rawat,

Rathee

et al. 2024

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Benzothiazole derivatives, a class of heterocyclic compounds, hold significant relevance in medicinal chemistry, materials science, and agrochemicals due to their diverse biological activities and applications. The conventional synthetic routes often involve harsh conditions and generate significant waste, prompting the exploration of more sustainable approaches. This work offers a comprehensive analysis of the developments in the use of heterogeneous catalysts for the production of benzothiazole derivatives, covering research from 2013 onward. Compared to traditional techniques, heterogeneous catalysts provide improved sustainability, efficiency, and recyclability. The review covers many heterogeneous catalysts and discusses their selectivity, recyclability, and catalytic activity. The utilization of heterogeneous catalysts is noteworthy as it facilitates the synthesis process's overall sustainability by allowing for milder reaction conditions, less environmental effect, and easier catalyst separation and recovery. The potential of heterogeneous catalysis in promoting the production of benzothiazole derivatives and satisfying the increasing need for these substances in various industrial applications is also highlighted.

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Bis-Cyclometalated Indazole and Benzimidazole Chiral-at-Iridium Complexes: Synthesis and Asymmetric Catalysis

Cited by 12 publications

References 52 publications

Anion-accelerated asymmetric Nazarov cyclization: access to vicinal all-carbon quaternary stereocenters

Anion-accelerated asymmetric Nazarov cyclization: access to vicinal all-carbon quaternary stereocenters

Metal Stereogenicity in Asymmetric Transition Metal Catalysis

Advancement in Heterogeneous Catalysts for the Synthesis of Benzothiazole Derivatives

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