Synthesis of 2,4,5-Trisubstituted Furans via a Triple C(sp³)–H Functionalization Reaction Using Rongalite as the C1 Unit

A highly efficient I2/Cu­(NO3)2·3H2O-mediated triple C­(sp3)–H functionalization reaction for the synthesis of 2,4,5-trisubstituted furans from aryl methyl ketones and rongalite by employing rongalite as a C1 unit has been developed. This method allows rapid access to (2-acyl-4-methylthio-5-aryl) furans. Preliminary mechanistic studies indicate that in situ generated dimethyl­(phenacyl)-sulfonium iodine and HCHO were probably the key intermediates in this transformation.本研究开发了一种以碘单质/三水合硝酸铜（I2/Cu(NO3)2·3H2O）为介导的高效三sp3碳氢键（C(sp3)–H）官能化反应，可通过芳基甲基酮与雕白粉（rongalite）为底物，且以雕白粉作为C1结构单元，合成2,4,5-三取代呋喃类化合物。该方法可快速获得(2-酰基-4-甲硫基-5-芳基)呋喃。初步机理研究表明，原位生成的二甲基(苯甲酰甲基)碘化锍与甲醛（HCHO）大概率为该转化过程的关键中间体。