title: Broadening the scope of group 4 hydroamination catalysis using a tethered ureate ligand.
abstract: A broadly applicable group-4-based precatalyst for the hydroamination of primary and secondary amines was developed. Screening experiments involving a series of amide and urea proligands led to the discovery of a tethered bis(ureate) zirconium complex with unprecedented reactivity in the intermolecular hydroamination of alkynes and the intramolecular hydroamination of alkenes. This catalyst system is effective with primary and secondary amines, 1,2-disubstituted alkenes, and heteroatom-containing functional groups, including ethers, silanes, amines, and heteroaromatics. The gem-disubstituent effect is not required for cyclization. The catalyst is generally regioselective for the anti-Markovnikov product of intermolecular alkyne hydroamination, and chemoselective for hydroamination over alpha-alkylation when forming 6- and 7-membered rings from aminoalkenes.
authors.affiliation: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, B.C., Canada V6T 1Z1.
authors.forename: David C
authors.initials: DC
authors.lastname: Leitch
authors.forename: Philippa R
authors.initials: PR
authors.lastname: Payne
authors.forename: Christine R
authors.initials: CR
authors.lastname: Dunbar
authors.forename: Laurel L
authors.initials: LL
authors.lastname: Schafer
mesh_terms: D000475:Alkenes / Q000737:chemistry; D000480:Alkynes / Q000737:chemistry; D000586:Amination; D000588:Amines / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D008024:Ligands; D014508:Urea
chemical_list: D000475:Alkenes; D000480:Alkynes; D000588:Amines; D008024:Ligands; D014508:Urea