Enantioselective synthesis of tunable chiral Clickphine P,N-ligands and their application in Ir-catalyzed asymmetric hydrogenation.
A small library of highly tunable chiral Clickphine P,N-ligands has been prepared in an enantioselective fashion by Cu(I)-catalyzed asymmetric propargylic amination using a single chiral complex and a subsequent in situ cycloaddition click reaction. The scope of the propargylic amination to yield optically active triazolyl amines is described. The amines are transformed in a one-pot procedure to the corresponding Ir-Clickphine complexes, which serve as catalysts for the asymmetric hydrogenation of di-, tri-, and tetrasubstituted unfunctionalized alkenes. Enantioselectivities of up to 90% ee were obtained in these hydrogenations, which are among the best reported in the case of the tetrasubstituted substrate 2-(4'-methoxyphenyl)-3-methylbut-2-ene (9) (87% ee). This is a demonstration of the effective use of the chiral pool, as from one chiral catalyst a library of chiral Ir complexes has been synthesized that can hydrogenate various alkenes with high selectivity.
Jeroen
J
Wassenaar
Remko J
RJ
Detz
Sandra Y
SY
de Boer
§Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
Martin
M
Lutz
‡Biomolecular Synthesis, van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
Jan H
JH
van Maarseveen
‡Biomolecular Synthesis, van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
Henk
H
Hiemstra
Joost N H
JN
Reek
D000586:Amination; D002073:Butanes / Q000737:chemistry*; D002384:Catalysis; D056831:Coordination Complexes / Q000138:chemical synthesis* / Q000737:chemistry; D003300:Copper / Q000737:chemistry; D006865:Hydrogenation; D007495:Iridium / Q000737:chemistry*; D008024:Ligands; D015394:Molecular Structure; D013237:Stereoisomerism
C000604156:2-(4'-methoxyphenyl)-3-methylbut-2-ene; D002073:Butanes; D056831:Coordination Complexes; D008024:Ligands; D007495:Iridium; D003300:Copper