Facile and Highly Diastereoselective Formation of a Novel Pentacyclic Scaffold by Direct Anodic Oxidation of 2,4‐Dimethylphenol

Abstract

Electrochemical oxidation of 2,4‐dimethylphenol directly provides pentacyclic systems being generated by an oxidative trimerization. The major pentacyclic scaffold is exclusively formed as a single diastereoisomer and is easily isolated. Three further pentacyclic compounds which occur in minor quantities were also fully characterized including their solid‐state structures. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Synthesis and Isolation of Enantiomerically Enriched Cyclopenta[b]benzofurans Based on Products from Anodic Oxidation of 2,4‐Dimethylphenol

“…In addition it was possible to verify the connection between the structures of 3a [13] and 3d [14] determined by Xray crystallography and the observed NMR spectroscopic data of both diastereomers [13,14] by calculating the 1 H and 13 C chemical shifts in silico which also ensured that the crystals picked for X-ray analysis corresponded to the bulk material in every case. To achieve this, the geometries of all four possible diastereomers (Scheme 5) were optimized at the B3LYP/6-311G(d,p) level of theory.…”

“…[12] In our recent research we have demonstrated that the polycyclic skeleton rac-2 can easily be obtained by oxidative coupling of 2,4-dimethylphenol using anodic oxidation (Scheme 1). [13] This reaction is the key step of a powerful methodology in a diversity-oriented synthetic approach to create multiple stereogenic centres on a multi-gram scale in a single synthetic step. [14] Furthermore, it offers access to numerous scaffolds of natural products in a highly chemo-, stereo-, regioselective and easy to perform manner.…”

ortho‐Selective Phenol‐Coupling Reaction by Anodic Treatment on Boron‐Doped Diamond Electrode Using Fluorinated Alcohols

“…Methyl-substituted phenols are prone to side reactions and 2,4-dimethylphenol in particular results in predominantly polycyclic architectures upon anodic treatment. [6] To circumvent this challenge we developed a boron-based template strategy [7,8] that can be performed on larger scale. [9] A protocol for the conversion of neat phenol (1) on boron-doped diamond (BDD) electrodes was developed in our laboratory.…”

Diversitäts‐orientierte Synthese von polycyclischen Gerüsten durch Umsetzung eines von 2,4‐Dimethylphenol abgeleiteten anodischen Zwischenproduktes

“…[16] Dieses Dehydrotetramer des Phenols kann leicht und in großen Mengen (bis zu 23 g pro Ansatz) erhalten werden. 2 ist leicht zu isolieren, da es während der Elektrolyse in der ungeteilten Zelle ausfällt, und wird als auschließliches Diastereomer erhalten.…”

“…Die thermische Behandlung oder -noch effizienter -die Umsetzung im Sauren von 2 [16] liefert den Spiropentacyclus 3 als alleiniges Produkt. [17] [18] erhält man das Dibenzofuran 6 als alleiniges Produkt.…”