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Titolo:
Five-coordinate [RuCl(P-P*)(2)]+ complexes containing chiral diphosphines:Application in the asymmetric cyclopropanation and epoxidation of olefins
Autore:
Stoop, RM; Bauer, C; Setz, P; Worle, M; Wong, TYH; Mezzetti, A;
Indirizzi:
ETH Zentrum, Anorgan Chem Lab, CH-8092 Zurich, Switzerland ETH Zentrum Zurich Switzerland CH-8092 Lab, CH-8092 Zurich, Switzerland
Titolo Testata:
ORGANOMETALLICS
fascicolo: 26, volume: 18, anno: 1999,
pagine: 5691 - 5700
SICI:
0276-7333(199912)18:26<5691:F[CCCD>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
RUTHENIUM COMPLEXES; CRYSTAL-STRUCTURE; ENANTIOSELECTIVE EPOXIDATION; ALKENE EPOXIDATION; CATALYZED EPOXIDATIONS; AGOSTIC INTERACTIONS; MOLECULAR-STRUCTURE; OXIDATIVE CLEAVAGE; TERT-BUTYL; LIGANDS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
83
Recensione:
Indirizzi per estratti:
Indirizzo: Mezzetti, A ETH Zentrum, Anorgan Chem Lab, CH-8092 Zurich, Switzerland ETHZentrum Zurich Switzerland CH-8092 2 Zurich, Switzerland
Citazione:
R.M. Stoop et al., "Five-coordinate [RuCl(P-P*)(2)]+ complexes containing chiral diphosphines:Application in the asymmetric cyclopropanation and epoxidation of olefins", ORGANOMETAL, 18(26), 1999, pp. 5691-5700

Abstract

The six-coordinate complexes trans-[RuCl2(P-P*)(2)] (P-P* = (S,S)-1,2-bis(1-naphthylphenylphosphino)ethane (bnpe), 2a; (S,S)-2,3-bis(diphenylphosphino)butane (chiraphos), 2b) have been prepared and structurally characterized. The X-ray studies of 2a,b show non-C-2-symmetric conformations of the substituents at the PPh2 groups in a highly crowded octahedral environment. Complexes 2a,b react with Tl[PF6] in CH2Cl2 to give the corresponding monochloro, cationic derivatives [RuCl(P-P*)(2)]PF6 (P-P*:= bnpe, 3a; chiraphos, 3b). The bnpe derivative 3a is five-coordinate both in the solid state (by X-ray investigation) and in solution (by P-31 NMR spectroscopy). The chiraphos analogue 3b apparently dimerizes in solution, depending on the solvent (CDCl3 or CD2Cl2) and on the concentration. Complexes 3a,b catalyze the decomposition of ethyl diazoacetate to give, in the presence of styrene, the corresponding cyclopropanation products with enantioselectivity up to 35% ee and E/Z ratios of about 55:45. Complexes 3a,b also catalyze the epoxidationof unfunctionalized olefins with iodosyl benzene as the primary oxidant. High olefin conversions and fair selectivity for the epoxide are observed, but both 3a and 3b give racemic epoxide.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/12/20 alle ore 12:57:57