1312767-17-1Relevant articles and documents
Amidate ligand design effects in zirconium-catalyzed enantioselective hydroamination of aminoalkenes
Ayinla, Rashidat O.,Gibson, Travis,Schafer, Laurel L.
, p. 50 - 60 (2011)
In situ generated axially chiral zirconium biphenyl amidate complexes are efficient precatalysts for the enantioselective intramolecular hydroamination of aminoalkenes, generating α-substituted pyrrolidines and piperidine with up to 74% ee. Five new chelating amide proligands and three new zirconium amidate complexes have been prepared and fully characterized in this investigation of ligand structure/catalyst function. Solid-state molecular structures of the complexes suggest that the observed moderate and highly variable enantioselectivities are a consequence of the multiple isomers accessible to this family of complexes, including a κ2-(O,O)- bonding motif. Thermal stability studies of the complexes further revealed the tendency of these complexes to undergo diastereoselective dimerization to afford homochiral dimers. These dimeric precatalysts are less efficient when used for the cyclization of aminoalkenes in comparison to their monomeric precursors. These results illustrate the variable coordination modes accessible to amidate ligands and suggest steric factors that must be considered in advanced ligand design.
Highly active and diastereoselective N,O- and N,N-yttrium complexes for intramolecular hydroamination
Lauterwasser, Frank,Hayes, Paul G.,Piers, Warren E.,Schafer, Laurel L.,Braese, Stefan
experimental part, p. 1384 - 1390 (2011/06/26)
The intramolecular hydroamination of aminoalkynes and unactivated aminoalkenes catalyzed by yttrium N,O- and N,N-complexes has been investigated. The N,N-yttrium complexes are highly active, catalyzing the conversion of a wide range of terminal aminoalkenes at room temperature, and internal aminoalkenes at elevated temperature, to yield pyrrolidine and piperidine products in high yields. A high diastereoselectivity of up to 23:1 is observed at 0°C with 1-methyl-4-pentenylamine as substrate.
Zirconium complexes supported by imidazolones: Synthesis, characterization, and application of precatalysts for the hydroamination of aminoalkenes
Hu, Yu-Cheng,Liang, Cheng-Feng,Tsai, Jie-Hong,Yap, Glenn P. A.,Chang, Ya-Ting,Ong, Tiow-Gan
experimental part, p. 3357 - 3361 (2010/10/04)
Dimeric zirconium benzyl and amide complexes supported by an imidazolone framework have been successfully synthesized and fully characterized. The amide complexes were found to be effective catalysts for intramolecular hydroamination of primary and second
