α-Haloenamides: Synthesis and Subsequent Transformations

Abstract

AbstractThe aim of this Short Review is to give an updated overview of the synthesis of α-haloenamides, which constitute a versatile subclass of enamides. α-Haloenamides can be prepared from ynamides, acetamides, or gem-dibromoalkenes in the presence of N-nucleophiles and easily converted into more elaborated structures through halogen-metal exchange and transition-metal-catalyzed cross-coupling reactions.1 Introduction2 α-Haloenamide Synthesis2.1 Hydrohalogenation of Ynamides2.1.1 cis-Hydrohalogenation of Ynamides2.1.2 trans-Hydrohalogenation of Ynamides2.2 α,β-Dihalogenation2.2.1 lodochlorination and Iodobromination of Ynamides2.2.2 Iodofluorination of Ynamides2.3 Chloroselenation of Ynamides2.4 Carbohalogenation of Ynamides2.4.1 Carboiodination2.4.2 Chloroallylation2.4.3 Chloro-benzhydrylation2.4.4 Chloro-γ-hydroxylation2.5 Vilsmeier–Haack Reactions2.6 Cross-Coupling Reaction of gem-Dibromoalkenes in the Presence of N-Nucleophiles3 Transformations of α-Haloenamides3.1 Suzuki and Sonogashira Reactions3.2 Heck Reaction3.3 Stille Reaction3.4 Miscellaneous Applications3.4 Carbonylation3.4.2 Reduction3.4.3 Synthesis of α-Fluoroimides3.4.4 Palladium-Catalyzed Intramolecular Cyclization4 Conclusion