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
Nickel-mediated carboxylative cyclization of enynes
作者:Masanori Takimoto、Takashi Mizuno、Yoshihiro Sato、Miwako Mori
DOI:10.1016/j.tetlet.2005.05.129
日期:2005.8
Nickel-mediated carboxylative cyclization of alpha,omega-enyne using carbon dioxide was investigated. Oxidative cycloaddition of enynes having an electron withdrawing group on alkene to a zero-valent nickel complex smoothly proceeded to provide nickelacyclopentene intermediates, which regioselectively reacted with CO2 at the Csp(3)-nickel bond, giving cyclized carboxylation products in good yields. (c) 2005 Elsevier Ltd. All rights reserved.
Chiral Pyrrolidines and Piperidines from Enantioselective Rhodium-Catalyzed Cascade Arylative Cyclization
A new rhodium-catalyzedasymmetricarylativecyclization of nitrogen-tethered alkyne-enoate with arylboronic acids is described. In this process two new carbon–carbon bonds and one stereocenter are formed, providing access to pyrrolidines and piperidines with good enantioselectivities by to the use of C1-symmetric chiral monosubstituted diene ligands.