52866-38-3Relevant articles and documents
Erbium triflate in ionic liquids: A recyclable system of improving selectivity in Diels-Alder reactions
Bortolini, Olga,De Nino, Antonio,Garofalo, Angelo,Maiuolo, Loredana,Procopio, Antonio,Russo, Beatrice
, p. 124 - 129 (2010)
The efficiency of Er(OTf)3 in promoting the Diels-Alder reactions between different dienes and dienophiles in ionic liquids has been investigated. Compared with the analogous cycloadditions performed in conventional solvents shorter reaction times are required to obtain good/excellent yields. In most cases an enhancement of regio- and endo:exo selectivity was observed. The role of the ionic liquid, as a function of the cationic part, i.e. the imidazolium based or the pyridinium based, is discussed well. The ILs containing the catalyst can be readily separated from the reaction products and recovered in very high purity for direct reuse, up to six cycles.
Phosphine-directed stereo- and regioselective Ni-catalyzed reactions of Grignard reagents with allylic ethers
Didiuk, Mary T.,Morken, James P.,Hoveyda, Amir H.
, p. 1117 - 1130 (2007/10/03)
Studies on the directed regio- and stereoselective Ni-catalyzed allylic substitution reactions involving methyl-and phenylmagnesium bromides and various acyclic and cyclic allylic ethers are reported. In the presence of a properly positioned internal Lewis base, C-C bonds can be formed catalytically and with excellent levels of selectivity. Internal chelation allows Ni-catalyzed C-C bond forming reactions that are otherwise non-selective, sluggish, or do not occur at all, to proceed to completion readily, in excellent yields, at ambient temperature and with high regio- and stereocontrol. Directed alkene isomerization highlights an especially attractive feature of the metal-catalyzed alkylation strategy: because the initial product contains a prostereogenic site that remains within reach of the internal Lewis base, it can be subjected to additional directed stereoselective manipulations.
