Broadening the scope of group 4 hydroamination catalysis using a tethered ureate ligand.
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.
Leitch
David C
DC
Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, B.C., Canada V6T 1Z1.
Payne
Philippa R
PR
Dunbar
Christine R
CR
Schafer
Laurel L
LL
D000475:Alkenes / Q000737:chemistry; D000480:Alkynes / Q000737:chemistry; D000586:Amination; D000588:Amines / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D008024:Ligands; D014508:Urea
D000475:Alkenes; D000480:Alkynes; D000588:Amines; D008024:Ligands; D014508:Urea