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Synthesis and Stereochemistry of the First Chiral (Imidazolinylidene)‐ and (Triazolinylidene)palladium(ii) Complexes
Author(s) -
Enders Dieter,
Gielen Heike,
Raabe Gerhard,
Runsink Jan,
Teles J. Henrique
Publication year - 1996
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19961291213
Subject(s) - chemistry , carbene , perchlorate , palladium , enantioselective synthesis , catalysis , yield (engineering) , medicinal chemistry , ligand (biochemistry) , stereochemistry , organic chemistry , ion , biochemistry , materials science , receptor , metallurgy
The reaction of three equiv. of a chiral imidazolium or triazolium perchlorate with one equiv. of Pd(OAc) 2 , an excess of NaI and a base leads to the corresponding chiral dicarbenediiodopalladium(II) complexes in chemical yields up to 98% and with the trans isomer as the major product ( 1, 2 ). If only one equiv. of the imidazolium or triazolium perchlorate is used, then dinuclear complexes with bridging iodine atoms are formed ( 3, 4 , chemical yield 92—94%). The latter can add Lewis basic ligands, e.g. amines, phosphanes or other carbenes, to give mononuclear complexes with one carbene ligand coordinated to the PdI 2 fragment ( 5, 6 ). Preliminary test experiments with these Pd(II) complexes as catalysts for an enantioselective Heck‐type reaction have been carried out.