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Facile Synthesis of Chiral Diphosphine‐Containing Multiple Dendrimeric Catalysts for Enantioselective Hydrogenation
Author(s) -
Zhao Liwen,
Liu Ji,
Feng Yu,
He Yanmei,
Fan Qinghua
Publication year - 2012
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.201200648
Subject(s) - chemistry , dendrimer , enantioselective synthesis , catalysis , rhodium , asymmetric hydrogenation , solvent , organic chemistry , combinatorial chemistry
A new kind of chiral diphosphine PyrPhos‐functionalized codendrimers have been synthesized via a liquid‐phase strategy in high yields. The resulting dendrimeric PyrPhos ligands were purified by a simple solvent precipitation without the need for chromatographic separation, and well characterized by 1 H, 13 C and 31 P NMR, MALDI‐TOF mass spectroscopy as well as elemental analysis. Their rhodium complexes were applied to the asymmetric hydrogenation of α ‐acetamido cinnamic acids. Excellent enantioselectivities were achieved, which are comparable to those with the corresponding small molecular catalysts. In addition, these codendrimeric catalysts showed better catalytic performance than the dendrimeric catalysts with Rh(PyrPhos) sites located in the focal point of poly(aryl ether) dendrons or in the periphery of poly(propyleneimine) dendrimers.