A. Ros, M. Alcarazo, Javier Iglesias‐Sigüenza
Aug 27, 2008
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0
Influential Citations
32
Citations
Journal
Organometallics
Abstract
The synthesis of 1-alkyl-1,2,4-triazolium salts containing chiral 4-dialkylamino substituents was accomplished by selective alkylation at N-1 of the corresponding 4-(dialkylamino)-1,2,4-triazoles. The latter were synthesized by reaction of N,N-dimethylformamidazine dihydrochloride with N,N-dialkylhydrazines in pyridine. Alternatively, the synthesis of 4-[(2S,5S)-2,5-diphenylpyrrolidin-1-yl]-1-phenyl-1,2,4-triazolium perchlorate was performed by reaction of 3-phenyl-1,3,4-oxadiazolium perchlorate with (2S,5S)-1-amino-2,5-diphenylpyrrolidine. These triazolium salts were transformed into neutral [RhCl(NHC)(COD)] complexes (NHC = 4-(dialkylamino)-1-alkyl(phenyl)triazol-5-ylidene) by reaction with [RhCl(COD)]2 in the presence of triethylamine. The products, featuring restricted C(carbene)−Rh bond rotation, were formed with high levels of selectivity in all cases, the de’s being >98% for complexes bearing the (2S,5S)-2,5-diphenylpyrrolidino group. A cationic heterobidentate NHC/S complex was also synthesized in...