Cycloaddition-based Formal C–H Alkynylation of Isoindoles Leading to the Synthesis of Air-stable Fluorescent 1,3-Dialkynylisoindoles

Reaction of N-alkylisoindoles with (bromoethynyl)triisopropylsilane afforded 1,3-bis(triisopropylsilylethynyl) isoindoles in high yields. The formal C–H alkynylation proceeds under transition-metal-free conditions through [4 + 2] cycloaddition of the pyrrole ring of isoindole with bromoalkyne followed by ring-opening of the product.