How electrophilic are 3-nitroindoles? Mechanistic investigations and application to a reagentless (4+2) cycloaddition

Abstract

The electrophilicity of 4 different 3–nitroindole derivatives has been evaluated by Mayr’s free linear energy relationship (log k(20 °C) = sN (E + N)) and reveals unexpected values for aromatic...

Efficient and Accurate Description of Diels‐Alder Reactions Using Density Functional Theory**

“…[6] In B2 cycloaddition, butadiene reacts with nitrobenzene as aromatic dienophile, a reaction linked to our interest in (4 + 2) Diels-Alder reactions with electron-poor aromatic compounds. [30][31][32][33][34][35] Note that in this case the cycloadduct will not differ by endo or exo approach, while the TS will. Here we consider the TS approach corresponding to the conformation which is lower in energy (the aromatic ring and the diene on the same side).…”

“…This led us to select B1 involving cyclopentadiene and acrylonitrile, a classical reaction that we had recently studied computationally under high pressure [6] . In B2 cycloaddition, butadiene reacts with nitrobenzene as aromatic dienophile, a reaction linked to our interest in (4+2) Diels‐Alder reactions with electron‐poor aromatic compounds [30–35] . Note that in this case the cycloadduct will not differ by endo or exo approach, while the TS will.…”

High pressure promoted dearomatization of nitroarenes by [4+2] cycloadditions with silyloxydienes

“…6 For example, [4+2] cycloadditions between electron-depleted arenes and electron-rich 1,3-dienes have been reported by us and by others. 7,8 The most commonly used substrates are nitroarenes, where harsh conditions are often needed to promote the cycloaddition process. For example, the reaction of 1-nitronaphthalene with Danishefsky diene 1a requires heating in benzene at 150 °C over several days and, unfortunately, leads to subsequent re-aromatization to furnish the corresponding phenanthrenol.…”

Predictive TDDFT Methodology for Aromatic Molecules UV‐Vis properties: from Benchmark to Applications

“…Next, compound 11 was synthesized by the reaction between 5-acetoxy-3-nitrobenzofuran and the Danishefsky diene, followed by re-aromatization on heating. [24] The synthetic sample exhibited four λ exp abs and four λ exp em maxima, which are listed and compared in Table 1. The precision of the statespecific method without correction gave values with errors ranging from 7.1 to 17.3 % in absorption and from 24.0 to 60.0 % in emission (see SI, Table S3).…”