Perhaloalkylatlon of Metal Enolates-Unconventional and Versatile

摘要

Halogenated natural products, especially those with di-and trichloromethyl groups (1-5), have recently come to the focus of interest of organic and medicinal chemists as well as biologists (Scheme 1). Trifluoromethyl-containing compounds do not occur in nature, but are common among pharmaceuticals (such as 6) and agrochemicals. Considerable progress has been made recently in the transition-metal-catalyzed coupling of CF_3 groups to C_(sp) and C_(sp2) systems. For the synthesis of simple aliphatic trifluoromethyl compounds a number of methodologies based on nucleophilic and electro-philic trifluoromethylation reagents have been developed. They are, however, not generally suitable for the α-trifluoro-methylation of carbonyl compounds. The arsenal of methods for the introduction of other di- or perhalomethyl groups to organic molecules is even more limited and traditionally restricted to the Kharasch addition.