The chiral phosphino-oxazoline ligand (S,R)-2-[4-(isopropyl)oxazol-2-yl]-2'-bis(3,5-dimethylphenylphosphino)-1,1'-binaphthyl, 6b, its Pd-dichloro complex, 9, the p-cyanoaryl complex [PdBr(p-NC-C6H4](6b)], 10, a model for the Heck reaction, the cationic 1,3-diphenylallyl derivative [Pd(eta(3)-PhCHCHCHPh)(6b)]OTf, 11, a model for the allylic allylation, and the Rh- and Ir-1,5-COD compounds [M(1,5-COD)(6b)]BF4, 12 and 13, respectively, have been prepared. In enantioselective catalytic experiments, the presence of the 3,5-dimethylphenyl groups generally increases the observed ee. The solid-state structure of PdCl2(6b), 9, has been determined. 2-D and variable-temperature NMR experiments suggest that one of the two 3,5-dimethyl P-aryl rings interacts selectively with the remaining ligands. Consequently, the entire chiral pocket becomes slightly more rigid and the correlation with substrate improves.
|Titolo:||Catalytic and structural studies on complexes of a binaphthyl-phosphino-oxazoline auxiliary : the meta dialkyl effect on enantioselectivity|
|Parole Chiave:||asymmetric allylic amination; chiral ruthenium complexes; hydrogenation reactions; amino-acids; palladium; alkylation; ligands; efficient; rhodium; 2,3-dihydrofuran|
|Settore Scientifico Disciplinare:||Settore CHIM/03 - Chimica Generale e Inorganica|
|Data di pubblicazione:||3-apr-2000|
|Digital Object Identifier (DOI):||10.1021/om990892f|
|Appare nelle tipologie:||01 - Articolo su periodico|