Facile Synthesis of Cyanoarenes from Quinones by Reductive ­Aromatization of Cyanohydrin Intermediates

Abstract

A novel synthesis of cyanoarenes from quinones by using PCl 3 as the reagent for reductive aromatization of cyanohydrin intermediates is reported. In situ IR spectroscopic measurements were conducted to monitor the reactions and to develop a convenient one-pot protocol. 1,4-Dicyanobenzene and 9,10-dicyanoanthracene were prepared by the new procedure.

A Versatile One‐Pot Access to Cyanoarenes from ortho‐ and para‐Quinones: Paving the Way for Cyanated Functional Materials

“…In the first report on the synthesis of cyanoarenes by reductive aromatization, we described the possibility of avoiding the formation of reaction byproducts by using PCl 3 instead of POCl 3 as the aromatization reagent for the second reaction step (Scheme , ii) . However, increasing amounts of DMF in the solvent mixture spoil this effect.…”

“…Despite these manifold applications of cyanoarenes, preparative approaches, until recently, have often involved either several synthetic steps or labor‐intensive purification procedures . This was overcome when we reported a synthetic method for the conversion of quinones to cyanoarenes via silylated cyanohydrin intermediates in a one‐pot reaction . A benefit of using quinones as the starting materials is their (commercial) availability in a wide range of different substitution patterns, including halogenated derivatives.…”

Effect of symmetric and asymmetric substitution on the optoelectronic properties of 9,10-dicyanoanthracene

“…Hence, we used a new cyanation method, which was recently introduced by some of us and which allows for the synthesis of both DCA and DCA derivatives from anthraquinones instead of dibromoanthracenes. 17,18 For the target compounds D1 and Q1 (with methoxy groups directly attached to the DCA), the cyanation was the final step of the synthesis (Scheme 1). The required precursors 2a-b were obtained by methylation of the respective hydroxyanthraquinones 1a-b.…”

“…Some of us have recently developed a new synthetic method that allows for an easy derivatisation of DCA with electrondonating substituents in positions 2 and 6. 17,18 Here, the choice of methoxy-functionalized substituents instead of other stronger electron donors is based on the prevention of lowering the fluorescence quantum yield and lifetime of the species too much. A too large difference in the reduction potentials of the electron donating and accepting moieties would lead to large Stokes shifts, placing the emission in a region where the radiative rate decreases and the non-radiative rate increases.…”

Double Ring-Closing Approach for the Synthesis of 2,3,6,7-Substituted Anthracene Derivatives

“…our recently developed method for the synthesis of substituted 9,10-anthracenedicarbonitriles (also known as 9,10dicyanoanthracenes). [10][11][12][13][14] However, as with our method, most available synthetic methods yield anthracene derivatives with substituents in the central 9-and 10-positions. The preparation of anthracene derivatives without substituents in these positions is often more challenging.…”