Iridium Catalyzed Carbocyclizations: Efficient (5+2) Cycloadditions of Vinylcyclopropanes and Alkynes
作者:Michaela-Christina Melcher、Henrik von Wachenfeldt、Anders Sundin、Daniel Strand
DOI:10.1002/chem.201405729
日期:2015.1.7
Third‐row transition metal catalysts remain a largely untapped resource in cycloaddition reactions for the formation of medium‐sized rings. Herein, we report the first examples of iridium‐catalyzed inter‐ and intramolecular vinylcyclopropane (VCP)–alkyne (5+2) cycloadditions. DFT modeling suggests that catalysis by iridium(I) proceeds through a mechanism similar to that previously reported for rhodium(I)‐catalyzed
A Cheap Metal for a “Noble” Task: Preparative and Mechanistic Aspects of Cycloisomerization and Cycloaddition Reactions Catalyzed by Low-Valent Iron Complexes
作者:Alois Fürstner、Keisuke Majima、Rubén Martín、Helga Krause、Egmont Kattnig、Richard Goddard、Christian W. Lehmann
DOI:10.1021/ja0777180
日期:2008.2.1
polyunsaturated substrates. The structures of ferrates 1 and 4 in the solid-state reveal the capacity of the reduced iron center to share electron density with the ligand sphere. This feature, coupled with the kinetic lability of the bound olefins, is thought to be responsible for the ease with which different enyne or diyne substrates undergo oxidative cyclization as the triggering event of the observed