Wavelength‐Gated Photochemical Synthesis of Phenalene Diimides
Florian Feist, Sarah L. Walden, Jessica Alves, Susanna V. Kunz, Aaron S. Micallef, Aidan J. Brock, John C. McMurtrie, Tanja Weil, James P. Blinco, Christopher Barner‐Kowollik
Abstract
Herein, we pioneer a wavelength-gated synthesis route to phenalene diimides. Consecutive Diels-Alder reactions of methylisophthalaldehydes and maleimides afford hexahydro-phenalene-1,6-diol diimides via 5-formyl-hexahydro-benzo[f]isoindoles as the intermediate. Both photoreactions are efficient (82-99 % yield) and exhibit excellent diastereoselectivity (62-98 % d.r.). The wavelength-gated nature of the stepwise reaction enables the modular construction of phenalene diimide scaffolds by choice of substrate and wavelength. Importantly, this synthetic methodology opens a facile avenue to a new class of persistent phenalenyl diimide neutral radicals, constituting a versatile route to spin-active molecules.