A catalytic amount of FeCl3 combined with benzoyl trifluoroacetone (Hbtfa) (FeCl3/Hbtfa = 1/2) was used to catalyze sulfonylation/acylation of diols and polyols using diisopropylethylamine (DIPEA) or potassium carbonate (K2CO3) as a base. The catalytic system exhibited high catalytic activity, leading to excellent isolated yields of sulfonylation/acylation products with high regioselectivities. Mechanism studies indicated that FeCl3 initially formed [Fe(btfa)3] (btfa = benzoyl trifluoroacetonate) with twice the amount of Hbtfa under basic conditions in the solvent acetonitrile at room temperature. Then, Fe(btfa)3 and two hydroxyl groups of the substrates formed a five- or six-membered ring intermediate in the presence of the base. The subsequent reaction between the cyclic intermediate and a sulfonylation reagent led to the selective sulfonylation of the substrate. All key intermediates were captured in the high-resolution mass spectrometry assay, therefore demonstrating this mechanism for the first time.

中文翻译：

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FeCl3结合苯甲酰三氟丙酮催化碳水化合物的区域选择性磺酰化/酰化反应及其机理研究。

使用二异丙基乙胺（DIPEA）或碳酸钾（K2CO3）作为碱，将催化量的FeCl3与苯甲酰基三氟丙酮（Hbtfa）（FeCl3 / Hbtfa = 1/2）结合用于催化二醇和多元醇的磺酰化/酰化。该催化体系表现出高催化活性，导致具有高区域选择性的磺酰化/酰化产物的优异分离产率。机理研究表明，FeCl3最初在碱性条件下于室温下于溶剂乙腈中以两倍的Hbtfa量形成[Fe（btfa）3]（btfa =苯甲酰基三氟丙酮酸酯）。然后，在碱的存在下，Fe（btfa）3和底物的两个羟基形成五元或六元环中间体。环状中间体和磺酰化试剂之间的随后反应导致底物的选择性磺酰化。所有关键中间体均在高分辨率质谱分析中捕获，因此首次证明了这种机理。