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Synthesis of Chiral C 2 ‐Symmetric Binucleating Ligands
Author(s) -
Fahrni Christoph J.,
Pfaltz Andreas
Publication year - 1998
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19980810304
Subject(s) - chemistry , stereocenter , thiourea , enantioselective synthesis , stereochemistry , pyroglutamic acid , pyrrole , catalysis , medicinal chemistry , combinatorial chemistry , amino acid , organic chemistry , biochemistry
The synthesis of a series of chiral enantiomerically pure C 2 ‐symmetric binucleating ligands is reported. Ligands of type 1 – 4 , which consist of a phenolic or heterocyclic unit bridging two chiral dihydrooxazole rings. are readily accessible from chiral amino alcohols. Ligands 5a and 5b are composed of a cyclic urea or thiourea unit, respectively, and two 3,4‐dihydro‐2 H ‐pyrrole rings containing a stereogenic center next to the N ‐atom. Compounds of this type are readily assembled from ethane‐1,2‐diamine and an imidothioic ester derived from pyroglutamic acid. These new ligands, which can coordinate two metals in close proximity to each other, are of interest regarding possible applications in asymmetric catalysis.