Chiral Heterobimetallic Bismuth-Rhodium Paddlewheel Catalysts: A Conceptually New Approach to Asymmetric Cyclopropanation.
Angew Chem Int Ed Engl
; 58(11): 3557-3561, 2019 Mar 11.
Article
em En
| MEDLINE
| ID: mdl-30672077
ABSTRACT
Cyclopropanation reactions of styrene derivatives with donor-acceptor carbenes formed inâ
situ are significantly more enantioselective when catalyzed by the heterobimetallic bismuth-rhodium complex 5 a endowed with N-phthalimido tert-leucine paddlewheel ligands rather than by its homobimetallic dirhodium analogue 1 a. This virtue is likely the result of two synergizing factors the conical shape of 5 a translates into a narrower calyx-like chiral binding site about the catalytically active Rh center; the Bi atom, although fully solvent exposed, does not decompose aryl diazoacetates and is hence incapable of promoting a racemic background reaction. Moreover, ligand variation proved that successful catalyst design mandates that the anisotropy of the conical heterobimetallic core be matched by proper directionality of the ligand sphere.
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01-internacional
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MEDLINE
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article