Silver and Gold Catalysis for Cycloisomerization Reactions

Abstract

We have focused our attention on cycloisomerization reactions involving silver-and gold-based homogeneous catalysis. This topic is divided into two parts: one relating to cycloisomerization with an allene group and the other with an alkyne group. In each case we have then studied different partners such as carbonyl/carboxy groups, imines, amides or alkenes. Reactions involving allene and alkyne systems as partners are also briefly reported, along with miscellaneous transformations. Our purpose is also to stimulate some dis-

ChemInform Abstract: Copper‐, Silver‐, and Gold‐Catalyzed Migratory Cycloisomerization Leading to Heterocyclic Five‐Membered Rings

“…15,21,28 Moreover, a major fraction of the corresponding multicomponent syntheses 10,29,30 also relies on the fundamental reactivities of these key acyclic precursors. Extensive research on the synthesis of aromatic heterocycles through transition-metal-catalyzed cycloisomerizations has been stimulated by the pioneering work of Heilbron (1947; Hg, 2-en-4-yne-1-ols), 31 Castro (1966; Cu, ortho -alkynyl anilines), 32 Miller (1969; Hg, alkynyl epoxides), 33 Huang (1986 and 1987; Pd, alkynyl ketones 34 and propargyl ketones 35 ), and Marshall (1990; Ag, Rh, allenyl ketones).…”

Gold‐Mediated Isomerization of ­Cyclooctyne to Ring Fused Olefinic Bicycles

“…[1][2][3][4][5][6][7][8][9][10][11][12] Cycloisomerization chemistry of 1,n-enynes, in which the alkene acts as the nucleophile towards an alkyne activated by gold(I) is particularly interesting since such reactions lead to intricate scaffolds in an atom economical manner. [1,5,6] An area of major research focus in recent years has been the chemistry of isolable alkyne-gold [13,14] and alkene-gold [13,[15][16][17] complexes since they serve as useful models for key intermediates believed to present in the above mentioned processes.…”

Metalltriflimidate sind bessere Katalysatoren für die organische Synthese als Metalltriflate – der Effekt eines stark delokalisierten Gegenions

“…Triflimidat-Katalysatoren wurden auch in anderen Über-sichten erwähnt, die als Schwerpunkt bestimmte Umwandlungsarten (Enin-Cycloisomerisierung, [62,63] Heterocyclisierung, [64,65] Carbocyclisierung [65] oder andere C-C-Kupplungen [66] ) oder bestimmte Katalysatorarten (HNTf 2 , [67] Oxazaborolidiniumtriflimidate, [68] Goldkatalysatoren [69,70] ) behandeln.…”