Cycloisomerization of 1,n-enynes via carbophilic activation.

Metal-catalyzed cycloisomerization of 1,n-enynes has appeared as a highly attractive methodology for the synthesis of original carbo- and heterocycles. This chapter intends to propose an overview of the recent and seminal advances in 1,n-enynes cycloisomerization reactions in the presence of carbophilic transition metals. The recent mechanistic insights, the enantioselective versions, and the applications in total synthesis are highlighted.

Mimicking polyolefin carbocyclization reactions: gold-catalyzed intramolecular phenoxycyclization of 1,5-enynes.

PPh(3)AuNTf(2) promotes highly efficient intramolecular phenoxycyclization reactions on 1,5-enynes under mild conditions. The original tricyclic and functionalized heterocycles were isolated in good to excellent yields. The 6-endo cyclization process is predominant and operates via a biomimetic cascade cation-olefin process.

Gold-catalyzed hydroamination/cycloisomerization reaction of 1,6-enynes.

An efficient Au(I) catalytic system is described for the hydroamination/cycloisomerization reaction of functionalized 1,6-enynes. The reaction leads to carbo- and heterocyclic amino derivatives in good to excellent yields. The cyclizations were conducted in the presence of PPh(3)AuCl/AgSbF(6) catalyst in THF or dioxane at room temperature.

Room temperature Au(I)-catalyzed exo-selective cycloisomerization of acetylenic acids: an entry to functionalized gamma-lactones.

A highly efficient gold-catalyzed cyclization reaction of various functionalized acetylenic acids is described. The cyclizations are conducted in the presence of Au(I) catalyst in acetonitrile at room temperature in a short reaction time. The reaction conditions are compatible with several functional groups, such as ester, alkene, alkyne, chloro, and free or protected alcohol, and lead to original gamma-lactones in good to excellent yields.