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ABSTRACT The direct cyclocondensation of ketones with 2‐mercaptoacetic acid remains challenging due to the lower electrophilicity and increased steric hindrance of ketone substrates compared to aldehydes. Herein, we report a Fe 3 O 4 nanoparticle‐catalyzed protocol that enables access to 2,2‐disubstituted 1,3‐oxathiolan‐5‐ones under solvent‐free microwave conditions. Reaction parameters were systematically optimized using a design‐of‐experiments (DoE) approach, identifying temperature and catalyst loading as key factors governing reactivity. Although a possible interplay between these variables was examined, no statistically significant interaction was identified within the studied experimental domain. Under the optimized conditions, a range of ketones afforded the corresponding oxathiolanones in moderate to excellent yields (up to 92%), including several previously unreported derivatives. The Fe 3 O 4 catalyst can be readily recovered by magnetic separation and reused for at least five consecutive cycles without significant loss of activity. Overall, this protocol provides a practical, solvent‐free, and recyclable approach to 2,2‐disubstituted 1,3‐oxathiolan‐5‐ones from ketone substrates under optimized conditions.
Lorenzo et al. (Fri,) studied this question.