The Chemistry of Gold–Allene Complexes

Abstract

In recent years, gold‐electrophilic activation of allenes has unraveled a huge potential for new reactivities toward the synthesis of complex molecules with synthetic or biological importance. Gold and allenes are a unique combination that has shown to be very versatile and give better reactivity, and in some cases is complementary to other metals. Coordination of gold to allenes is more complex than coordination to a simple olefin or alkyne, and several types of structures can be predicted depending on the atoms involved in the coordination. The nature of the gold–allene interaction defines the reactivity of these complexes, which can be modulated toward the desired product by slight changes in the catalysts or reaction conditions. New reactions involving gold–allene complexes for the formation of carbon–heteroatom or carbon–carbon bond formation will be discussed in this chapter, including inter‐ and intramolecular examples of nucleophilic additions, and inter‐ and intramolecular cycloaddition and cycloisomerization reactions with alkenes, dienes, alkynes, and other allenes.

Gold(I)-Catalyzed Activation of Alkynes for the Construction of Molecular Complexity

“…Gold allenic intermediates 347 derived from 1,3-acyloxy migration (see Scheme 109 ) can be trapped by other functional groups to give of a range of different compounds. 299 In situ generated ketone-allene substrates 358 were used as substrates for a gold(I)-mediated tandem oxacyclization/[4 + 2] cycloaddition cascade to afford highly substituted oxacycles 359 with excellent stereocontrol (Scheme 112 ). 300 Nucleophilic allenes have also been generated in situ by a gold(I)-catalyzed rearrangement of propargylic esters and then used for intermolecular C(sp 3 )–C(sp 2 ) bond formation reactions.…”