Access to Se/S-Containing Heterocycles via Hexafluoroisopropanol-Mediated Tandem Wolff Rearrangement/Cyclization

Herein, we report a novel and efficient formal [3 + 3] cyclization strategy for the synthesis of 1,3-selenazines. This protocol relies on the hexafluoroisopropanol (HFIP)-mediated Wolff rearrangement of alkynyl diazoalkyl ketones to in situ generate key alkynyl ketene intermediates, which are sequentially trapped by selenoamides via a cascade reaction to furnish the target 1,3-selenazines. Furthermore, the biological evaluation results demonstrated the promising potential of the resulting organoselenium cyclic scaffolds as lead structures for the development of fungicidal agrochemicals.