Iridium phosphite-oxazoline catalysts for the highly enantioselective hydrogenation of terminal alkenes.
A modular library of readily available phosphite-oxazoline ligands (L1-L16a-f) has been successfully applied for the first time in the Ir-catalyzed asymmetric hydrogenation of a broad range of highly unfunctionalized 1,1,-disubstituted terminal alkenes. Enantioselectivities up to >99% and full conversions were obtained in several 1,1-disubstituted alkenes, including substrate classes that have never been asymmetrically hydrogenated before (i.e., 1,1-heteoraryl-alkyl, 1,1-diaryl, trifluoromethyl, etc.). The results indicated that these catalytic systems have high tolerance to the steric and electronic requirements of the substrate and also to the presence of a neighboring polar group. The asymmetric hydrogenations were also performed using propylene carbonate as solvent, which allowed the Ir catalyst to be reused and maintained the excellent enantioselectivities.
Mazuela
Javier
J
Departament de Quimica Fisica i Inorganica, Universitat Rovira i Virgili, Campus Sescelades, C/ Marcel.li Domingo, s/n, 43007 Tarragona, Spain.
Verendel
J Johan
JJ
Coll
Mercedes
M
Schäffner
Benjamín
B
Börner
Armin
A
Andersson
Pher G
PG
Pàmies
Oscar
O
Diéguez
Montserrat
M
D000475:Alkenes / Q000737:chemistry*; D002384:Catalysis; D006865:Hydrogenation; D007495:Iridium / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry*; D010080:Oxazoles / Q000737:chemistry*; D017905:Phosphites / Q000737:chemistry*; D013237:Stereoisomerism; D013379:Substrate Specificity
D000475:Alkenes; D009942:Organometallic Compounds; D010080:Oxazoles; D017905:Phosphites; D007495:Iridium