Diels–Alder Reaction of Tropones with Arynes: Synthesis of Functionalized Benzobicyclo[3.2.2]nonatrienones

Abstract

A new procedure for the mild, practical, and scalable Diels-Alder reaction of tropones with arynes is reported. Differently substituted tropones undergo selective [4 + 2] cycloaddition with arynes generated in situ by the fluoride-induced 1,2-elimination of 2-(trimethylsilyl)aryl triflates, allowing the formation of functionalized benzobicyclo[3.2.2]nonatrienone derivatives in moderate to good yields. In addition, the photophysical properties of the cycloadducts are presented.

Three-Component, Diastereoselective [6 + 3] Annulation of Tropone, Imino Esters, and Arynes

“…In the presence of tropone, the 2:1 adduct of imino ester and aryne leading to the formation of imidazolidines can compete over the desired three-component [6 + 3] annulation product . Moreover, tropone can add to arynes in a Diels–Alder reaction to form the bicyclic products . As a consequence of the careful optimization studies, herein we report the three-component and diastereoselective [6 + 3] annulation of tropone, imino esters, and arynes leading to the transition-metal-free access to azabicyclo[4.3.1]­decadienes.…”

Synthesis of Substituted Tropones and Advancement for the Construction of Structurally Significant Skeletons

“…In the year, 2014 Akkattu T. Biju and co‐workers synthesized benzobicyclo[3.2.2]nonatrienone derivatives 152 from the Diels‐Alder reaction between tropone 34 and arynes which were formed from 2‐(trimethylsilyl)aryl triflates 151 (Scheme 25) (Table 4). [92] A variety of fluoride sources (KF, CsF, TBAF) and solvents (CH 3 CN, THF) were screened but the best yield (77 %) was obtained in presence of 151 (1.5 equiv) and CsF (3.0 equiv). This synthetic protocol had a broad substrate scope.…”

Gold(I)-Catalyzed [8+4] Cycloaddition of 1,4-All-Carbon Dipoles with Tropone

“…High-order cycloaddition reaction represents an extraordinary tool for synthesizing a large number of important medium-sized polycyclic scaffolds in a fairly straightforward manner . In this scene, the tropone and its derivatives have proven to be versatile 4π, 6π, or 8π synthons in processing [4+2], [4+6], [6+3], [6+4], [6+6], [8+2], and [8+3] high-order cycloadditions to build various bridged- or fused-cyclic skeletons, which are highly privileged backbones in the synthesis of bioactive molecules and natural products . In particular, numerous studies have revealed that the use of tropones as a 8π component in cycloaddition with suitable partners can result in efficient access to bicyclic frameworks.…”