Developments in the dehydrogenative electrochemical synthesis of 3,3′,5,5′-tetramethyl-2,2′-biphenol

Abstract The symmetric biphenol 3,3′,5,5′‐tetramethyl‐2,2′‐biphenol is a well‐known ligand building block and is used in transition‐metal catalysis. In the literature, there are several synthetic routes for the preparation of this exceptional molecule. Herein, the focus is on the sustainable electrochemical synthesis of 3,3′,5,5′‐tetramethyl‐2,2′‐biphenol. A brief overview of the developmental history of this inconspicuous molecule, which is of great interest for technical applications, but has many challenges for its synthesis, is provided. The electro‐organic method is a powerful, sustainable, and efficient alternative to conventional synthesis to obtain this symmetric biphenol up to the …

Electrochemical Allylic Oxidation of Olefins: Sustainable and Safe.

The power you're supplying: With the application of an optimized electrochemical approach, the allylic oxidation of olefins, which is an important C-H activation process that provides access to enones, becomes a sustainable, versatile, and potent key reaction for organic synthesis.

Large, Highly Modular Narrow-Gap Electrolytic Flow Cell and Application in Dehydrogenative Cross-Coupling of Phenols

The successive scale-up of electrochemical reactions is crucial with regard to the implementation of technical electro-organic syntheses. Therefore, we developed a scalable modular parallel-plate e...

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.

Frontispiece: A Novel Cathode Material for Cathodic Dehalogenation of 1,1‐Dibromo Cyclopropane Derivatives

A Novel Cathode Material for Cathodic Dehalogenation of 1,1-Dibromo Cyclopropane Derivatives.

Leaded bronze turned out to be an excellent cathode material for the dehalogenation reaction of cyclopropanes without affecting the strained molecular entity. With this particular alloy, beneficial properties of lead cathodes are conserved, whereas the corrosion of cathode is efficiently suppressed. The solvent in the electrolyte determines whether a complete debromination reaction is achieved or if the process can be selectively stopped at the monobromo cyclopropane intermediate. The electroorganic conversion tolerates a variety of functional groups and can be conducted at rather complex substrates like cyclosporine A. This approach allows the sustainable preparation of cyclopropane deriva…

Elektrochemische allylische Oxidation von Olefinen: nachhaltig und sicher

Electrochemical Arylation Reaction

Arylated products are found in various fields of chemistry and represent essential entities for many applications. Therefore, the formation of this structural feature represents a central issue of contemporary organic synthesis. By the action of electricity the necessity of leaving groups, metal catalysts, stoichiometric oxidizers, or reducing agents can be omitted in part or even completely. The replacement of conventional reagents by sustainable electricity not only will be environmentally benign but also allows significant short cuts in electrochemical synthesis. In addition, this methodology can be considered as inherently safe. The current survey is organized in cathodic and anodic con…

Selective and Scalable Dehydrogenative Electrochemical Synthesis of 3,3′,5,5′-Tetramethyl-2,2′-biphenol

3,3′,5,5′-Tetramethyl-2,2′-biphenol is a compound of high technical significance, as it exhibits superior properties as building block for ligands in the transition-metal catalysis. However, side reactions and overoxidation are challenging issues in the conventional synthesis of this particular biphenol. Here, an electrochemical method is presented as powerful and sustainable alternative to conventional chemical strategies, which gives good yields up to 51%. Despite using inexpensive and well-available bromide-containing supporting electrolytes, the issue of bromination and general byproduct formation is effectively suppressed by adding water to the electrolyte. Additionally, the scalabilit…

ChemInform Abstract: Electrochemical Allylic Oxidation of Olefins: Sustainable and Safe

The power you're supplying: With the application of an optimized electrochemical approach, the allylic oxidation of olefins, which is an important C-H activation process that provides access to enones, becomes a sustainable, versatile, and potent key reaction for organic synthesis.

Supporting-Electrolyte-Free and Scalable Flow Process for the Electrochemical Synthesis of 3,3′,5,5′-Tetramethyl-2,2′-biphenol

The most efficient electrochemical synthesis of 3,3′,5,5′-tetramethyl-2,2′-biphenol by dehydrogenative coupling is reported. The electrolysis is performed supporting-electrolyte-free in 1,1,1,3,3,3...

Electrosynthesis of 3,3′,5,5’-tetramethyl-2,2′-biphenol in flow

Abstract3,3′,5,5’-Tetramethyl-2,2′-biphenol is well known as an outstanding building block for ligands in transition-metal catalysis and is therefore of particular industrial interest. The electro-organic method is a powerful, sustainable, and efficient alternative to conventional synthetic approaches to obtain symmetric and non-symmetric biphenols. Here, we report the successive scale-up of the dehydrogenative anodic homocoupling of 2,4-dimethylphenol (4) from laboratory scale to the technically relevant scale in highly modular narrow gap flow electrolysis cells. The electrosynthesis was optimized in a manner that allows it to be easily adopted to different scales such as laboratory, semit…

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 1899693: Experimental Crystal Structure Determination

Related Article: Maximilian Selt, Stamo Mentizi, Dieter Schollmeyer, Robert Franke, Siegfried R. Waldvogel|2019|Synlett|30|2062|doi:10.1055/s-0039-1690706

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 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