This work presents the first synthetic route toward 3-unsubstituted c-fused isothiazoles in three steps from commercially available saturated ketones, exemplified for more than 15 hitherto undescribed c-fused isothiazoles. Unlike prior methods relying on prefunctionalized scaffolds, the unsubstituted core enables versatile late-stage functionalization at the 3-position, demonstrated by six different functionalization pathways.
Ivanova et al. (Tue,) studied this question.