New role for photoexcited organic dye, Na2 eosin Y via the direct hydrogen atom transfer (HAT) process in photochemical visible-light-induced synthesis of spiroacenaphthylenes and 1H-pyrazolo[1,2-b] phthalazine-5,10-diones under air atmosphere

A green multi-component tandem strategy for metal-free synthesizing spiroacenaphthylenes and 1H-pyrazolo [1,2-b]phthalazine-5,10-diones by Knoevenagel-Michael cyclocondensation is reported via organic dye Na2 eosin Y-derived photoexcited states functions as a direct hydrogen atom transfer (HAT) catalyst via visible lightmediated in aqueous ethyl lactate at ambient temperature under air atmosphere. This study paves the new role for further use of a metal-free organic dye with commercial availability and inexpensiveness, Na2 eosin Y in photochemical synthesis with use of the lowest amount of catalyst, energy-effectiveness, excellent yields, operational simplicity, time-saving aspects of the reaction and high atom economy, thus meeting some features of sustainable and green chemistry. Notably, this cyclization is also runnable on gram scale, which highlights the potentiality of using this reaction in industrial uses.

Automated summary

A green multi-component tandem strategy for metal-free synthesizing spiroacenaphthylenes and 1H-pyrazolo [1,2-b]phthalazine-5,10-diones is reported, using Na2 eosin Y as a direct hydrogen atom transfer catalyst under visible light-mediated conditions. The reaction demonstrates high atom economy, excellent yields and simplicity, showcasing its potential for industrial uses.