Exploiting the Divergent Reactivity of Aryl–Palladium Intermediates for the Rapid Assembly of Fluorene and Phenanthrene Derivatives

Yan-hua, Zhao; Mariampillai, Brian; Candito, David A.; Laleu, Benoît; M, Li; Lautens, Mark

doi:10.1002/anie.200805780

Cited by 160 publications

(45 citation statements)

References 42 publications

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“…We are highly interested in the development of cross‐coupling reactions for material science and we realized that domino reactions such as norbornene(NBE)‐mediated palladium cascades hold great potential for not only tackling the sequential reactions in one pot, but also providing access to the ubiquitous aryl halides. However, the homo‐coupling of aryl halides might be facile, while directing groups, which assist in the controlled heterobiaryl coupling, might be difficult to be removed after reactions . Recently, the use of a carboxylic acid as traceless directing group has received significant attention and Hong's group recently demonstrated this strategy with an impressive tandem synthesis of acenes (Scheme c) .…”

Section: Methodsmentioning

confidence: 99%

Regioselective Synthesis of Polycyclic and Heptagon‐embedded Aromatic Compounds through a Versatile π‐Extension of Aryl Halides

et al. 2017

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A versatile π-extension reaction was developed based on the three-component cross-coupling of aryl halides, 2-haloarylcarboxylic acids, and norbornadiene. The transformation is driven by the direction and subsequent decarboxylation of the carboxyl group, while norbornadiene serves as an ortho-C-H activator and ethylene synthon via a retro-Diels-Alder reaction. Comprehensive DFT calculations were performed to account for the catalytic intermediates.

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Section: Methodsmentioning

confidence: 99%

Regioselective Synthesis of Polycyclic and Heptagon‐embedded Aromatic Compounds through a Versatile π‐Extension of Aryl Halides

et al. 2017

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“…Seminal work by Lautens has shown that such an aryl-Pd(II) species could attack an adjacent carbonyl group, but this has been limited to an intramolecular transformation. 15 Clearly, many challenges can be envisioned with this redox-neutral strategy, including the difficulty of controlling site-selectivity and the choice of suitable electrophiles. Thus, at this preliminary stage, we have been focused on a simplified system with one electrophile being a proton source (Scheme 1D).…”

Section: The Bigger Picturementioning

confidence: 99%

Redox-Neutral ortho Functionalization of Aryl Boroxines via Palladium/Norbornene Cooperative Catalysis

Liu

Dong

2019

Chem

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A redox-neutral ortho functionalization of aryl boroxines via palladium/ norbornene cooperative catalysis is developed. The ortho amination and acylation are achieved with carboxylic acid anhydrides and O-benzoyl hydroxylamines as an electrophile, respectively, whereas protonation occurs at the ipso position. This transformation avoids using either extra oxidants and reductants or stoichiometric bases and acids. In addition, orthogonal chemoselectivity between aryl iodide and boroxine moieties is demonstrated for pathway divergence. HIGHLIGHTS First redox-neutral direct ortho functionalization of aryl boroxines Proton as the second electrophile coupled at the ipso position Avoiding stoichiometric bases in the Pd/NBE catalysis Orthogonal chemoselectivity between aryl iodide and boroxine moieties Li et al., Chem 5, 929-939 April 11, SUMMARYPalladium/norbornene (Pd/NBE) cooperative catalysis, also known as the Catellani reaction, has become an increasingly useful method for site-selective arene functionalization; however, certain constraints still exist because of its intrinsic mechanistic pathway. Herein, we report a redox-neutral ortho functionalization of aryl boroxines via Pd/NBE catalysis. An electrophile, such as carboxylic acid anhydrides or O-benzoyl hydroxylamines, is coupled at the boroxine ortho position, and a proton as the second electrophile is introduced at the ipso position. This reaction does not require extra oxidants or reductants and avoids stoichiometric bases or acids, thereby tolerating a wide range of functional groups. In particular, orthogonal chemoselectivity between aryl iodide and boroxine moieties is demonstrated, which could be used to control reaction sequences. Finally, a deuterium-labeling study supports the ipso protonation pathway. This unique mechanistic feature could inspire the development of a new class of Pd/NBE-catalyzed transformations.

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“…Lautens et al in 2009 reported that norbornene mediated CÀ H activation accesses the substituted fluorenone (54) from obromobenzaldehyde (49) or o-bromo aryl ester (53) with 1iodonaphthalene (52) by changing catalyst composition and reaction conditions (heating reaction medium at 150°C in microwave reactor) (Scheme 11). [34] Recently Sorensen et al reported the transient directing group mediated fluorenone synthesis via double CÀ H activation. Anthranilic acid acts as a transient directing group (Scheme 12).…”

Section: Intermolecular Synthesis Of Fluorenonesmentioning

confidence: 99%

A Perspective on Synthesis and Applications of Fluorenones

et al. 2020

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Fluorenones are important constituents in material, medical and chemical sciences with potential applications in various domains. The key factors responsible for the diverse usage of fluorenones in material sciences are their intriguing and tunable photo, as well as physico‐chemical properties. Besides this, the presence of conjugated poly‐(en)ynes in the fluorenones makes them molecules of interest in material sciences. Fluorenones show various biological activities like antibiotics, anticancer, antiviral, and neuromodulatory, etc. Organic chemists are developing various protocols for the synthesis of fluorenones. Despite several protocols developed for their synthesis since 1931, there is no review covering their entire synthetic protocols. This review includes several classical and novel synthetic approaches for the synthesis of fluorenones. Furthermore, we delineated the mechanism by which they have been synthesized.

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Exploiting the Divergent Reactivity of Aryl–Palladium Intermediates for the Rapid Assembly of Fluorene and Phenanthrene Derivatives

Cited by 160 publications

References 42 publications

Regioselective Synthesis of Polycyclic and Heptagon‐embedded Aromatic Compounds through a Versatile π‐Extension of Aryl Halides

Regioselective Synthesis of Polycyclic and Heptagon‐embedded Aromatic Compounds through a Versatile π‐Extension of Aryl Halides

Redox-Neutral ortho Functionalization of Aryl Boroxines via Palladium/Norbornene Cooperative Catalysis

A Perspective on Synthesis and Applications of Fluorenones

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