Ru-Catalyzed Cyclization of Terminal Alkynals to Cycloalkenes
摘要:
Cycloalkenes can be efficiently prepared by a new Ru-catalyzed cyclization of terminal alkynals. Under appropriate conditions, cycloisomerizations to conjugated aldehydes may be observed. Both processes involve catalytic Ru vinylidenes.
Nickel-mediated cyclization of enynes under an atmosphere of carbon dioxide
作者:Masanori Takimoto、Takashi Mizuno、Miwako Mori、Yoshihiro Sato
DOI:10.1016/j.tet.2006.03.121
日期:2006.8
Nickel-mediated carboxylation of α,ω-enyne was investigated. In the presence of a stoichiometric amount of zero-valent nickel complex, enynes having an electron-withdrawing group on alkene reacted with carbon dioxide via intramolecular cyclization to afford cyclic carboxylic acids in good yields. Various heterocyclic compounds were prepared by this carboxylative cyclization protocol. The reaction seems
Rhodium-Catalyzed Tandem Addition–Cyclization–Rearrangement of Alkynylhydrazones with Organoboronic Acids
作者:Kyoungmin Choi、Hoyoon Park、Chulbom Lee
DOI:10.1021/jacs.8b05561
日期:2018.8.22
approach allows alkyne-tethered hydrazones and organoboronic acids to undergo a cascade of addition-cyclization-rearrangement reactions to provide cycloalkene products. The process is initiated by the rhodium-catalyzed addition-cyclization and completed with the allylic diazene rearrangement. The reaction can also be rendered asymmetric by using chiral diene ligands for the rhodium catalyst, whereby
presence of a catalytic amount of rhodium(I) complex having a diolefin ligand to afford 2-alkylidenecyclopentanols through the regioselective addition of an arylrhodium(I) species across the carbon-carbontriple bond, followed by intramolecular nucleophilic addition of the resulting vinylrhodium(I) species to the carbonyl group.
Ru-Catalyzed Cyclization of Terminal Alkynals to Cycloalkenes
作者:Jesús A. Varela、Carlos González-Rodríguez、Silvia G. Rubín、Luis Castedo、Carlos Saá
DOI:10.1021/ja0610434
日期:2006.8.1
Cycloalkenes can be efficiently prepared by a new Ru-catalyzed cyclization of terminal alkynals. Under appropriate conditions, cycloisomerizations to conjugated aldehydes may be observed. Both processes involve catalytic Ru vinylidenes.
Rhodium-catalyzed arylative cyclization of alkynones induced by addition of arylboronic acids
Alkynones react with arylboronic acids in the presence of a rhodium(I) catalyst to afford four- and five-membered-ring cyclic alcohols equipped with a tetrasubstituted exocyclic olefin. The cyclic allylic alcohol skeleton is constructed by the carbon-carbon bond formation between the carbonyl group and an alkenylrhodium(I) intermediate formed by the regioselective addition of an arylrhodium(I) species across the carbon-carbon triple bond. (c) 2007 Elsevier Ltd. All rights reserved.