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The article highlights the advances and perspectives in Transition Metal-Catalyzed 1,4-Functionalizations of Unactivated 1,3-Enynes for the Synthesis of Allenes. It mentions that the selective insertion of the C—C double bond in 1,3-enynes into metal-FG bonds leads to the formation of intermediates and also highlights the methods for the synthesis of allenes as the isomerization of alkynes.

Abstract: Die erste Rhodium(I)‐katalysierte enantioselektive intermolekulare C sp 3 ‐H‐Aktivierung verschiedener gesättigter Aza‐Heterocyclen einschließlich Tetrahydrochinolinen, Piperidinen, Piperazinen, Azetidinen, Pyrrolidinen, Azepanen und anderen wird beschrieben. Die Kombination eines Rhodium(I)‐Präkatalysators und eines chiralen einzähnigen Phosphonitliganden ist ein leistungsfähiges katalytisches System, um aus einfachen Ausgangsmaterialien eine Vielzahl von wichtigen enantiomeren‐angereicherten Heterocyclen herzustellen. Die C sp 3 ‐H‐Aktivierung von Tetrahydrochinolinen ist aufgrund der benachbarten C sp 2 ‐H‐Bindung besonders anspruchsvoll. Diese redoxneutrale Methode bietet einen neuen Syntheseweg für α‐N‐arylierte Heterocyclen mit hoher Chemoselektivität und Enantioselektivität von bis zu 97 % ee. [ABSTRACT FROM AUTHOR]

Abstract: The first rhodium(I)‐catalyzed enantioselective intermolecular C sp 3 –H activation of various saturated aza‐heterocycles including tetrahydroquinolines, piperidines, piperazines, azetidines, pyrrolidines, and azepanes is presented. The combination of a rhodium(I) precatalyst and a chiral monodentate phosphonite ligand is shown to be a powerful catalytic system to access a variety of important enantio‐enriched heterocycles from simple starting materials. Notably, the C sp 3 –H activation of tetrahydroquinolines is especially challenging due to the adjacent C sp 2 −H bond. This redox‐neutral methodology provides a new synthetic route to α‐N‐arylated heterocycles with high chemoselectivity and enantioselectivity up to 97 % ee. [ABSTRACT FROM AUTHOR]

Abstract: The first rhodium(I)‐catalyzed enantioselective intermolecular C sp 3 –H activation of various saturated aza‐heterocycles including tetrahydroquinolines, piperidines, piperazines, azetidines, pyrrolidines, and azepanes is presented. The combination of a rhodium(I) precatalyst and a chiral monodentate phosphonite ligand is shown to be a powerful catalytic system to access a variety of important enantio‐enriched heterocycles from simple starting materials. Notably, the C sp 3 –H activation of tetrahydroquinolines is especially challenging due to the adjacent C sp 2 −H bond. This redox‐neutral methodology provides a new synthetic route to α‐N‐arylated heterocycles with high chemoselectivity and enantioselectivity up to 97 % ee. [ABSTRACT FROM AUTHOR]

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A manganese(I)/Lewis acid cocatalyzed direct C−H propargylation with high selectivity has been developed. BPh3 was discovered to not only promote the reactivity, but also enhance the selectivity. Secondary, tertiary, and even quaternary carbon centers at the propargylic position could be directly constructed. Both internal and terminal alkynes are easily accessible. The chirality was successfully transferred from an axially chiral allene to central chirality. The reactivity of the manganese catalyst in this reaction was found to be unique among transition metal catalysts. [ABSTRACT FROM AUTHOR]

Copyright of Angewandte Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Eine einfache Route zur Synthese von Isochinolin‐3‐onen durch Kooperation von B(C6F5)3‐ und Cp*CoIII‐katalysierter C‐H‐Bindungsaktivierung von Iminen mit Diazoverbindungen wird beschrieben. Der Einsatz von katalytischen Mengen an B(C6F5)3 ermöglicht eine hocheffiziente Reaktion, sodass selbst labile NH‐Imine als Substrate eingesetzt werden können. CoIII‐operative Katalyse: Die erste einfache Route zur Synthese von Isochinolin‐3‐onen mittels kooperativer C‐H‐Aktivierungskatalyse durch B(C6F5)3 („BCF” im Bild) und Cp*CoIII (Cp*=C5Me5) wird vorgestellt. Das neue katalytische System ist hochreaktiv, sodass labile NH‐Imine als Substrate eingesetzt werden können. [ABSTRACT FROM AUTHOR]

A facile route toward the synthesis of isoquinolin-3-ones through a cooperative B(C6F5)3- and Cp*CoIII-catalyzed C−H bond activation of imines with diazo compounds is presented. The inclusion of a catalytic amount of B(C6F5)3 results in a highly efficient reaction, thus enabling unstable NH imines to serve as substrates. [ABSTRACT FROM AUTHOR]

Based on a Co(III)-catalyzed C-H activation of imines such as (I), the reaction with diazo compounds offers a convenient method for the synthesis of isoquinolin-3-ones. [ABSTRACT FROM AUTHOR]

Hydroarylation is an effective strategy to rapidly increase the complexity of organic structures by transforming flat alkene moieties into three-dimensional frameworks. Many strategies have already been developed to achieve the hydroarylation of styrenes, however most of these reports examine the hydroarylation of unpolar, β-mono- or β-unsubstituted styrenes, while exploring mainly electron-rich benzene nucleophiles. Herein, we report a mild and general catalytic system for the selective hydroheteroarylation of multiply substituted styrenes and heteroaromatic styrenes. Mechanistic analysis of the reaction led to the discovery of commercially available 2,2':5',2''-terthiophene as a key reagent., (© 2021 Wiley-VCH GmbH.)

The synthesis and photophysical properties of a soluble amide-embedded coronene is reported. The key step in this synthesis is the twofold C-H activation of diazaperylene by a rhodium(III)Cp* catalyst. This unprecedented structural motif shows intense fluorescence in the near infrared region with a small Stokes shift and a distinct vibronic structure, which exhibits a slight extent of negative solvatochromism. Comparison of this compound with some relevant compounds revealed the importance of the amide incorporation in the peripheral concave region including an angular position to retain high aromaticity reflecting that of parent coronene. Treatment of this compound with Lewis acid B(C 6 F 5 ) 3 formed a bis-adduct, which exhibited enhanced aromaticity as a consequence of the increased double bond character of the amide C-N bonds., (© 2020 Wiley-VCH GmbH.)

The first rhodium(I)-catalyzed enantioselective intermolecular Csp3 -H activation of various saturated aza-heterocycles including tetrahydroquinolines, piperidines, piperazines, azetidines, pyrrolidines, and azepanes is presented. The combination of a rhodium(I) precatalyst and a chiral monodentate phosphonite ligand is shown to be a powerful catalytic system to access a variety of important enantio-enriched heterocycles from simple starting materials. Notably, the Csp3 -H activation of tetrahydroquinolines is especially challenging due to the adjacent Csp2 -H bond. This redox-neutral methodology provides a new synthetic route to α-N-arylated heterocycles with high chemoselectivity and enantioselectivity up to 97 % ee., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

An unprecedented Mn I -catalyzed (2-indolyl)methylation of heteroarenes is reported. This method makes use of an aromatizing cascade strategy to install a (2-indolyl)methyl group into target molecules, thereby leading to the expedient synthesis of previously challenging and important unsymmetrical diheteroarylmethanes, in particular bis(2-indolyl)methanes. The proposed cascade process comprises the reorganization of multiple bonds with controlled regioselectivity and high atom economy and can be performed on a gram-scale. Furthermore, a metal-free C-H propargylation is observed. The diverse application of this method is also demonstrated., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A manganese(I)/Lewis acid cocatalyzed direct C-H propargylation with high selectivity has been developed. BPh 3 was discovered to not only promote the reactivity, but also enhance the selectivity. Secondary, tertiary, and even quaternary carbon centers at the propargylic position could be directly constructed. Both internal and terminal alkynes are easily accessible. The chirality was successfully transferred from an axially chiral allene to central chirality. The reactivity of the manganese catalyst in this reaction was found to be unique among transition metal catalysts., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A strategy is reported in which traceless directing groups (TDGs) are used to promote the redox-neutral Mn I -catalyzed regioselective synthesis of N-heterocycles. Alkyne coupling partners bearing a traceless directing group, which serves as both the chelator and internal oxidant, were used to control the regioselectivity of the annulation reactions. This operationally simple approach is highly effective with previously challenging unsymmetrical alkyne systems, including unbiased dialkyl alkynes, with perfect regioselectivity. The simple conditions and the ability to carry out synthesis on a gram scale underscore the usefulness of this method. The application of this strategy in the concise synthesis of the bioactive compound PK11209 and the pharmaceutical moxaverine is also described., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A Mn I -catalyzed regioselective C-H allenylation is reported that allows a broad range of 2-allenylindoles to be synthesized regioselectively on a gram scale under simple conditions. Notably, a highly efficient chirality transfer was observed (up to 93 % ee) in this transformation. This procedure was further found to allow, for the first time, the direct preparation of ketones by Mn I -catalyzed C-H activation. Mechanistic investigations revealed that the precoordination of the oxygen atom to the manganese center as well as the congested tertiary carbon atom in the propargylic carbonates play a crucial role., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)