A Highly Active System for the Metal-Free Aerobic Photocyanation of Tertiary Amines with Visible Light: Application to the Synthesis of Tetraponerines and Crispine A

A highly efficient metal-free catalytic system for the aerobic photocyanation of tertiary amines with visible light is reported. The use of air as terminal oxidant offers an improved safety profile compared with pure oxygen, the used compact fluorescent lamp (CFL) light sources are highly economical, and no halogenated solvents are required. This system not only proves to be effective for a wide variety of trialkylamines, pharmaceuticals, and alkaloids but remarkably also allows the lowest catalyst loading (0.00001 mol% or 0.1 ppm) ever reported for an organic dye. Bruylants reactions and C-alkylation/decyanations were performed on the obtained α-aminonitriles to demonstrate the postfunctio…

Total Synthesis of (-)-Oxycodone via Anodic Aryl-Aryl Coupling.

A fully regio- and diastereoselective electrochemical 4a–2′-coupling of a 3′,4′,5′-trioxygenated laudanosine derivative enables the synthesis of the corresponding morphinandienone. This key intermediate is further transformed into (−)-oxycodone through conjugate nucleophilic substitution for E-ring closure and [4 + 2] cycloaddition with photogenerated singlet oxygen to accomplish diastereoselective hydroxylation at C-14. The anodic transformation provides high yields and can be performed under constant current conditions both in a simple undivided cell or in continuous flow.

Sunflow: Sunlight Drives Fast and Green Photochemical Flow Reactions in Simple Microcapillary Reactors - Application to Photoredox and H-Atom-Transfer Chemistry

“Sunflow“ – The combination of a microcapillary reactor in continuous flow mode with sunlight as the most sustainable energy source imaginable was applied to a range of photoredox and H-atom-transfer reactions making them both fast and green.

Back Cover: A Regio- and Diastereoselective Anodic Aryl-Aryl Coupling in the Biomimetic Total Synthesis of (−)-Thebaine (Angew. Chem. Int. Ed. 34/2018)

Eine regio- und diastereoselektive anodische Aryl-Aryl-Kupplung in der biomimetischen Totalsynthese von (−)-Thebain

Light-Induced Alkylation of (Hetero)aromatic Nitriles in a Transition-Metal-Free C–C-Bond Metathesis

A light-induced C–C-σ-bond metathesis was achieved through transition-metal-free activation of an unstrained C(sp3)–C(sp3)-σ-bond in 1-benzyl-1,2,3,4-tetrahydroisoquinolines. A photoredox-mediated single-electron oxidation of these precursor amines yield radical cations which undergo a homolytic cleavage of a C(sp3)–C(sp3)-σ-bond rather than the well-known α-C–H-scission. The resulting carbon-centered radicals are used in the ipso-substitution of (hetero)aromatic nitriles proceeding through another single-electron transfer-mediated C–C-bond cleavage and formation.

ChemInform Abstract: Light Induced C-C Coupling of 2-Chlorobenzazoles with Carbamates, Alcohols, and Ethers.

A light induced, transition-metal-free C-C coupling reaction of 2-chlorobenzazoles with aliphatic carbamates, alcohols, and ethers is presented. Inexpensive reagents, namely sodium acetate, benzophenone, water, and acetonitrile, are employed in a simple reaction protocol using a cheap and widely available 25 W energy saving UV-A lamp at ambient temperature.

Rücktitelbild: Eine regio- und diastereoselektive anodische Aryl-Aryl-Kupplung in der biomimetischen Totalsynthese von (−)-Thebain (Angew. Chem. 34/2018)

A Regio- and Diastereoselective Anodic Aryl-Aryl Coupling in the Biomimetic Total Synthesis of (-)-Thebaine.

The biosynthesis of thebaine is based on the regioselective, intramolecular, oxidative coupling of (R)-reticuline. For decades, chemists have sought to mimic this coupling by using stoichiometric oxidants. However, all approaches to date have suffered from low yields or the formation of undesired regioisomers. Electrochemistry would represent a sustainable alternative in this respect but all attempts to accomplish an electrochemical synthesis of thebaine have failed so far. Herein, a regio- and diastereoselective anodic coupling of 3',4',5'-trioxygenated laudanosine derivatives is presented, which finally enables electrochemical access to (-)-thebaine.

Light Induced C-C Coupling of 2-Chlorobenzazoles with Carbamates, Alcohols, and Ethers.

A light induced, transition-metal-free C-C coupling reaction of 2-chlorobenzazoles with aliphatic carbamates, alcohols, and ethers is presented. Inexpensive reagents, namely sodium acetate, benzophenone, water, and acetonitrile, are employed in a simple reaction protocol using a cheap and widely available 25 W energy saving UV-A lamp at ambient temperature.

ChemInform Abstract: A Highly Active System for the Metal-Free Aerobic Photocyanation of Tertiary Amines with Visible Light: Application to the Synthesis of Tetraponerines and Crispine A.

A highly efficient metal-free catalytic system for the aerobic photocyanation of tertiary amines with visible light is reported. The use of air as terminal oxidant offers an improved safety profile compared with pure oxygen, the used compact fluorescent lamp (CFL) light sources are highly economical, and no halogenated solvents are required. This system not only proves to be effective for a wide variety of trialkylamines, pharmaceuticals, and alkaloids but remarkably also allows the lowest catalyst loading (0.00001 mol% or 0.1 ppm) ever reported for an organic dye. Bruylants reactions and C-alkylation/decyanations were performed on the obtained α-aminonitriles to demonstrate the postfunctio…

CCDC 1831234: Experimental Crystal Structure Determination

Related Article: Alexander Lipp, Dorota Ferenc, Christoph Gütz, Mario Geffe, Nina Vierengel, Dieter Schollmeyer, Hans J. Schäfer, Siegfried R. Waldvogel, Till Opatz|2018|Angew.Chem.,Int.Ed.|57|11055|doi:10.1002/anie.201803887

CCDC 1894341: Experimental Crystal Structure Determination

Related Article: Alexander Lipp, Maximilian Selt, Dorota Ferenc, Dieter Schollmeyer, Siegfried R. Waldvogel, Till Opatz|2019|Org.Lett.|21|1828|doi:10.1021/acs.orglett.9b00419

CCDC 1894340: Experimental Crystal Structure Determination

Related Article: Alexander Lipp, Maximilian Selt, Dorota Ferenc, Dieter Schollmeyer, Siegfried R. Waldvogel, Till Opatz|2019|Org.Lett.|21|1828|doi:10.1021/acs.orglett.9b00419

CCDC 1831233: Experimental Crystal Structure Determination

Related Article: Alexander Lipp, Dorota Ferenc, Christoph Gütz, Mario Geffe, Nina Vierengel, Dieter Schollmeyer, Hans J. Schäfer, Siegfried R. Waldvogel, Till Opatz|2018|Angew.Chem.,Int.Ed.|57|11055|doi:10.1002/anie.201803887

CCDC 1894339: Experimental Crystal Structure Determination

Related Article: Alexander Lipp, Maximilian Selt, Dorota Ferenc, Dieter Schollmeyer, Siegfried R. Waldvogel, Till Opatz|2019|Org.Lett.|21|1828|doi:10.1021/acs.orglett.9b00419

CCDC 1831232: Experimental Crystal Structure Determination

Related Article: Alexander Lipp, Dorota Ferenc, Christoph Gütz, Mario Geffe, Nina Vierengel, Dieter Schollmeyer, Hans J. Schäfer, Siegfried R. Waldvogel, Till Opatz|2018|Angew.Chem.,Int.Ed.|57|11055|doi:10.1002/anie.201803887

CCDC 1831236: Experimental Crystal Structure Determination

Related Article: Alexander Lipp, Dorota Ferenc, Christoph Gütz, Mario Geffe, Nina Vierengel, Dieter Schollmeyer, Hans J. Schäfer, Siegfried R. Waldvogel, Till Opatz|2018|Angew.Chem.,Int.Ed.|57|11055|doi:10.1002/anie.201803887

CCDC 1831235: Experimental Crystal Structure Determination

Related Article: Alexander Lipp, Dorota Ferenc, Christoph Gütz, Mario Geffe, Nina Vierengel, Dieter Schollmeyer, Hans J. Schäfer, Siegfried R. Waldvogel, Till Opatz|2018|Angew.Chem.,Int.Ed.|57|11055|doi:10.1002/anie.201803887