Synthesis of α-fluoromethyl ketones via allene epoxides

✍ Scribed by Marek M. Kabat

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 208 KB
• Volume: 42
• Category: Article
• ISSN: 0022-1139
• DOI: 10.1016/s0022-1139(00)83935-4

✦ Synopsis

Academy of Sciences, ti-Fluoromethyl ketones are formed via the reaction of allene epoxides with tetrabutylammonium fluoride trihydrate (TBAF-3H20) in THF. The syntheses of fluorine-containing analogues of some biologically active ketones have attracted considerable attention. owing to their activity as competitive enzyme inhibitors (11. Whereas efficient mild methods for preparation of trifluoromethyl ketones have recently been developed [2,3], the corresponding monofluorinated derivatives [3] remain less accessible. In 1976 Chan and coworkers have reported [4] that monosubstituted methyl ketones may be prepared from aldehydes or ketones and 1-lithio-1-(trimethylsilyl)ethylene in a four-step procedure involving allene epoxides (cf. the Scheme). Different *substituted ketones have been prepared by this method [41; however, no formation of ti-fluoromethyl ketones was observed. In the present studies the original procedure of these authors was modified to permit an efficient approach to a wide range of fluorine-substituted ketones. The modification consists of the application of different leaving groups for allene epoxide formation, and of the use of nucleophilic fluorine in the reaction with allene epoxide.