Gold-Catalyzed 5- and 6-exo-dig Selective Cyclizations of Alkynyl Silyl Enol Ethers: Efficient Method for [3+2] and [4+2] Annulations onto α,β-Enones
作者:Kooyeon Lee、Phil Ho Lee
DOI:10.1002/adsc.200700304
日期:2007.9.3
An efficient method for the annulation of five- and six-membered rings onto α,β-enones is described via gold-catalyzed 5- and 6-exo-dig selective cyclizations of alkynyl silyl enolethers.
Gold-catalysed room-temperature cycloisomerisation of alkynes and unactivated enolisable ketones
作者:Paul W. Davies、Christelle Detty-Mambo
DOI:10.1039/c003473h
日期:——
The cycloisomerisation of simple keto-alkynes proceeds at room temperature under the mild conditions of gold catalysis. Bicyclic fused and spiro compounds can be obtained by overall 5-exo and 6-exo carbon–carbon bond-forming cyclisations.
gold catalysis highly enantioenriched bicyclic enones are available via an operationally simple one-pot procedure. Iminium-ion activation by cinchona alkaloid-derived primary amine catalysts induces the Michael addition of propargylated malononitriles and cyanoacetates to α,β-unsaturated ketones. The resulting intermediates undergo an exo-dig cyclization, forming a new C–C bond followed by double-bond