Aravindan Jayaraman，Han-Sung Kim, Jaerim Park and Sunwoo Lee* Department of Chemistry, Chonnam National University, Gwangju 61186, Republic of Korea Email: sunwoo@chonnam.ac.kr 2,2,2-Trichloroacetophenone derivatives were synthesized via decarboxylative trichlorination from arylpropiolic acids and trichloroisocyanuricacid (TCCA). The reaction was performed in the presence of water at room temperature, and the desired products were obtained in good yields. The reaction showed good functional group tolerance towards halide, cyano, nitro, ketone, ester and aldehyde groups. In addition, the 2,2,2-trichloroacetophenone derivatives were readily transformed into esters, amides, and hydrazides. Based on experiments with H₂¹⁸O (water¹⁸O), we proposed a cationic reaction pathway as the mechanism and suggested two different pathways for producing aryl- and alkyl-substituted propiolic acids. Acknowledgments This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (NRF-2015R1A4A1041036, NRF-2017R1A2B2002929).