Copper complexes pseudohalides

The enhanced solubilities of copper(I) halides or pseudohalides in aqueous solutions of alkali or ammonium halides are due to the formation of anionic complexes (37, 121, 134, 263) ... 

Complexes of Copper(i).— In most of the copper(i) complexes whose structures have been described during the period of this survey the co-ordination at the metal atom is close to tetrahedral co-ordination numbers of two or three are much less common, while values greater than four are found exclusively in cluster compounds. The structures of mono- and bi-nuclear copper(i)-phosphine complexes have aroused a great deal of interest, and an attempt has been made to explain the observed variations in the lengths of Cu -P bonds. Attention has also been directed at polymeric copper compounds containing bridging halide or pseudohalide ions a number of such systems are described in the section on mixed-valence copper(i)-copper(n) compounds. 

In the last years a powerful set of protocols involving C(sp )-N bond fonnation have emerged as reliable and convenient alternatives for the assembly of enamine and enamides. The latter methods consist of mostly palladium-catalyzed oxidative amidations of alkenes [38] and both palladium-[39] and copper-catalyzed crosscouplings [40] between generally vinyl halides or pseudohalides and amines or amides. In this review, recent advances in both types of processes will be disclosed illustrating, likewise, their synthetic value by describing total syntheses of natural products of high structural complexity. 

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