Transition Metal- and Oxidant-Free Base-Mediated Selenation of Bicyclic Arenes at Room Temperature

Abstract

Bicyclic arenyl selenides are of much importance because of their pharmaceutical applications. A simple method for their synthesis has been developed by a reaction of 2-naphthol and styrenyl selenocyanate/diaryl diselenide in the presence of a base at room temperature. The selenation occurs exclusively at the 1-position of 2-naphthol unit. The reactions are relatively fast (2–4 h) and high yielding. A library of substituted naphthyl styrenyl and naphthyl aryl selenides are obtained by this procedure.

Base‐Promoted Direct Chalcogenylation of 2‐Naphthols

“…When the reaction was performed with Na 2 CO 3 , the desired product was detected in only 57% yield (Table , entry 2), which could be explained by the inferior solubility and lower dissolution rate constant of this base in DMSO . On the other hand, despite the considerably higher solubility of Cs 2 CO 3 in DMSO, the yield of 3 a was 71% (Table , entry 3), in contrast to Ranu's results with the same reagents at lower temperature and lower base concentration . Furthermore, the use of KHCO 3 and NaHCO 3 gave lower yields of 3 a (Table , entries 4–5).…”

“…Considering the advantages of these bases, it is desirable to unfold a new base‐mediated selanylation of bicyclic arenes with the easily handled diorganoyl diselenides. During the final phase of our work, Ranu and co‐workers described the direct selanylation of the 2‐naphthol unit with styrenyl selenocyanates or diaryl diselenides in the presence of a base at room temperature (Scheme , a) . This method employed 2.0 equivalents of base and required an inert atmosphere, besides the mechanism of this transformation was not evaluated.…”

Synthetic strategies for aryl/heterocyclic selenides and tellurides under transition-metal-catalyst free conditions

“…Ranu et al have reported an efficient method for the synthesis of bicyclic di-aryl and styrenyl/aryl selenides by using 2-naphthanol and diarylselenides/sterenylselenocyanate respectively without using any oxidant or additive at room temperature (Scheme 18). 34 Selenation occurs at the 1-position of 2-naphthols through C-H bond functionalization in dimethyl sulfoxide (DMSO) in presence of Cs 2 CO 3 as base. A series of 2-naphthanol containing both electron donating and withdrawing groups reacts with both diaryldiselenide and vinyl selenocyante successfully to give corresponding napthtyl-aryl selenides and napthyl vinyl selenides respectively by following an electrophilic aromatic substitution mechanism in good to excellent yields.…”

Metal‐Free Synthesis of Unsymmetrical Aryl Selenides and Tellurides via Visible Light‐Driven Activation of Arylazo Sulfones

“…[32] Accordingly, the preparation of heteroaryl selenides and tellurides under oxidative (e.g. in the presence of Oxone or iodine, an example in Scheme 1b) [33][34][35][36] or basic [37][38][39] conditions, has been reported. In this regards, great attention has been given to the development of protocols based on the generation of an aryl radical as the key-intermediate that is trapped by a chalcogenide derivative (e.g.…”