UV-light-absorbing decatungstate anion is more efficient and permits the use of a smaller excess of hydrogen donor than the aromatic ketones, although the ketones could be excited by visible light. Further intramolecular selectivity studies revealed that aromatic ketones afforded a higher proportion of functionalization at the acetalic versus the ethereal positions than did the decatungstate anion.
研究了脂肪族氧杂环(二
氧戊环、1,3-
二恶烷或环状
碳酸酯)中通过光催化氢原子转移和随后用
苯基乙烯基砜捕获所得自由基的 C-H 到 C-C 转化。比较了三种不同光催化剂,即四丁基十
钨酸
铵和
芳香酮噻吨酮和
9-芴酮的性能。尽管酮可以被可见光激发,但吸收紫外线的十
钨酸阴离子更有效,并且允许使用比
芳香酮更少过量的氢供体。进一步的分子内选择性研究表明,与十
钨酸盐阴离子相比,
芳香酮在
缩醛与醚位置提供更高比例的官能化。