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 intermediate...