1H-Isoindolynes: Arynes Accessible by a One-Pot, Ambient Temperature, Three-Component Cascade

Area of Science:

• Organic Chemistry
• Synthetic Methodology
• Reaction Mechanisms

Background:

• Arynes are highly reactive intermediates crucial in organic synthesis.
• Developing new aryne precursors and efficient synthetic routes remains an active area of research.

Purpose of the Study:

• To introduce a novel class of arynes, 1H-isoindolynes.
• To establish a new, efficient, and convergent synthetic strategy for accessing these compounds.

Main Methods:

• A room temperature cascade reaction involving primary propargylic diynol, propargylic aminodiyne, and an aryne-trapping agent.
• Oxidation to generate a 2,4-diynal intermediate in situ.
• Mechanistic studies using 1H NMR spectroscopy, control reactions, and density functional theory (DFT) calculations.

Main Results:

• Successful synthesis of 1H-isoindolynes via a multi-step cascade reaction.
• The cascade involves imine condensation, E-to-Z isomerization, hexadehydro-Diels-Alder cycloisomerization, and aryne trapping.
• Good to excellent yields of isoindolyne adducts were achieved.
• DFT calculations and spectroscopic data provided insights into the reaction mechanism.

Conclusions:

• A new class of arynes, 1H-isoindolynes, has been synthesized.
• A novel, convergent cascade reaction provides efficient access to these compounds.
• The study elucidates key mechanistic aspects of this transformation.