604758-11-4Relevant academic research and scientific papers
Gold(I)-catalyzed [2 + 2]-cycloaddition of allenenes
Luzung, Michael R.,Mauleon, Pablo,Toste, F. Dean
, p. 12402 - 12403 (2008/09/17)
A cationic phosphinegold(I)-catalyzed intramolecular [2 + 2]-cycloaddition between an allene and an alkene to form alkylidene?cyclobutanes is described. Additionally, the reported cycloisomerization reaction provides access to enantioenriched bicyclo-[3.2.0] structures using chiral biarylphosphinegold(I) complexes as catalysts. Copyright
Rhodium Complex-Catalyzed Cycloisomerization of Allenenes: Exo and Endo Cyclization Depending on the Auxiliary Ligands
Makino, Tatsuya,Itoh, Kenji
, p. 395 - 405 (2007/10/03)
In the presence of a catalytic amount of a rhodium(I) complex, allenenes undergo cycloisomerization reactions resulting in the selective formation of exo-alkylidenecarbocycles and heterocycles. In the catalytic system of rhodium complexes with triaryl phosphites, cyclic 1,4- or 1,5-dienes are formed in good to excellent yields in the formal exo-cyclization mode via the metallacycle intermediate having an exo-alkylidene moiety. In this cycloisomerization, (E)- and (Z)-allenenes are transformed stereospecifically to the corresponding cyclic (E)- and (Z)-1,4-dienes, respectively. On the other hand, the reactions under carbon monoxide atmosphere exclusively afford seven-membered-ring products through an endo-mode cyclization. The unusual cyclization involves an allylic C-H activation process. The allenene bearing a silicon substituent at the olefinic terminus incorporates carbon monoxide to give the corresponding [2+2+1] cycloaddition product. This result apparently indicates that the catalysis of the rhodium complex is explained in terms of the oxidative cyclization of an allenene to furnish the key exo-alkylidene metallacycle intermediate at the first stage of the catalysis.
