The Reaction of Carboxylic Acid Esters with RfMgBr: A Convenient Synthesis of Perfluoroalkyl Ketones

• Published in: European Journal of Organic Chemistry 2010-12, Vol.2010 (36), p.7012-7019
• Main Authors: Xue, Can, He, Guangke, Fu, Chunling, Xue, Liqin, Lin, Zhenyang, Ma, Shengming
• Format: Article
• Language: English
• Subjects: Aliphatic compounds; Chemistry; Esters; Exact sciences and technology; Fluo­rine; Grignard reaction; Ketones; Organic chemistry; Perfluoroalkanes; Preparations and properties
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/ejoc.201000887

An efficient method for the preparation of the synthetically attractive perfluoroalkyl ketones through the reaction of readily available alkenoates, alkynoates, or regular carboxylic esters with perfluoroalkyl Grignard reagents at –70 to –60 °C in diethyl ether with moderate to good yields was developed. The reaction stopped at the ketone stage, with no further reaction to form the tertiary alcohols being observed. DFT calculations confirmed that the perfluoroalkyl‐substituted ketones are less electrophilic as compared to ordinary ketones. Perfluoroalkyl ketones can be prepared from the reaction of alkenoates, alkynoates, or regular carboxylic acid esters with perfluoroalkyl Grignard reagents at –70 to –60 °C in Et2O with moderate to goodyields. DFT calculation results are consistent with the experimental observation of a less electrophilic carbonyl moiety in the perfluoroalkyl ketones when compared with ordinary ketones.