表面改性
化学
吲哚试验
光催化
烷基
色胺
卡宾
组合化学
反应性(心理学)
光化学
衍生化
阳离子聚合
光催化
有机化学
催化作用
医学
病理
物理化学
高效液相色谱法
生物化学
替代医学
作者
Claire Empel,Sripati Jana,Łukasz Ciszewski,Katarzyna Zawada,Chao Pei,Dorota Gryko,René M. Koenigs
标识
DOI:10.1002/chem.202300214
摘要
The C-H functionalization of indole heterocycles constitutes a key strategy to leverage the synthesis of endogenous signaling molecules such as tryptamine or tryptophol. Herein, we report on the photocatalytic reaction of ethyl diazoacetate with indole, which shows an unusual solvent dependency. While C2-functionalization occurs under protic conditions, the use of aprotic solvents leads to a complete reversal of selectivity and exclusive C3-functionalization occurs. To rationalize for this unexpected reactivity switch, we have conducted detailed theoretical and experimental studies, which suggest the participation of a triplet carbene intermediate that undergoes initial C2-functionalization. A distinct cationic [1,2]-alkyl radical migration then leads to formation of C3-functionalized indole. We conclude with the application of this photocatalytic reaction to access oxidized tryptophol derivatives including gram-scale synthesis and derivatization reactions.
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