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Titolo:
A new family of chelating diphosphines with a transition metal stereocenter in the backbone: Novel applications of "chiral-at-rhenium'' complexes in rhodium-catalyzed enantioselective alkene hydrogenations
Autore:
Kromm, K; Zwick, BD; Meyer, O; Hampel, F; Gladysz, JA;
Indirizzi:
Univ Erlangen Nurnberg, Inst Organ Chem, D-91054 Erlangen, Germany Univ Erlangen Nurnberg Erlangen Germany D-91054 -91054 Erlangen, Germany Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA Univ Utah Salt Lake City UT USA 84112 Chem, Salt Lake City, UT 84112 USA
Titolo Testata:
CHEMISTRY-A EUROPEAN JOURNAL
fascicolo: 9, volume: 7, anno: 2001,
pagine: 2015 - 2027
SICI:
0947-6539(20010504)7:9<2015:ANFOCD>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
ASYMMETRIC CATALYSIS; PLANAR CHIRALITY; ABSOLUTE-CONFIGURATION; FERROCENYL LIGANDS; ORGANOSULFUR COMPOUNDS; CARBON CONFIGURATION; PHOSPHIDO COMPLEXES; OPTICAL RESOLUTION; SULFIDE COMPLEXES; DYNAMIC BEHAVIOR;
Keywords:
asymmetric hydrogenation; amino acids; catalyst; conformation analysis; heterobimetallic;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
78
Recensione:
Indirizzi per estratti:
Indirizzo: Gladysz, JA Univ Erlangen Nurnberg, Inst Organ Chem, Henkestr 42, D-91054 Erlangen, Germany Univ Erlangen Nurnberg Henkestr 42 Erlangen Germany D-91054 y
Citazione:
K. Kromm et al., "A new family of chelating diphosphines with a transition metal stereocenter in the backbone: Novel applications of "chiral-at-rhenium'' complexes in rhodium-catalyzed enantioselective alkene hydrogenations", CHEM-EUR J, 7(9), 2001, pp. 2015-2027

Abstract

The title compounds are accessed by sequences starting with racemic and enantiomerically pure [(eta (C5H5)-C-5)Re(NO)(PPh3)(CH3)]. Reactions with chlorobenzene/HBF4, PPh2H, and tBuOK give the phosphido complex [(eta (5)-C5H5)Re(No) (PPh3)(PPh2)] (3). Reactions with Ph3C+BF4-, PPh2H, and tBuOK give the methylene homologue [(eta (5)-C5H5)Re(No)(PPh3)(CH2PPh2)] (9). Treatment of 3 or 9 with nBuLi or tBuLi and then PPh2Cl gives the diphosphido systems [(eta (5)-C5H4PPh2)Re(NO)(PPh3)((CH2)(n)PPh2)] (n = 0/1, 5/11), Reactions of 5 and 11 with [Rh(NBD)Cl](2)/AgPF6 (NBD = norbornadiene) give the rhenium/rhodium chelate complexes [(eta (5)-C5H4PPh2)Re(No)(PPh3)((mu -CH2)(n)PPh2)Rh- (NBD)]+PF6- (n=0/1, 6(+)/12(+) PF6-; 30-32% overall from commercialRe,(CO),,). The crystal structures of 6(+) PF6- and 12(+) PF6- are compared to those of 3 and 9, and other rhodium complexes of chelating bis(diphenylphosphines). The chiral pockets defined by the PPh2 groups show unusual features. Four alkenes of the type (Z)RCH=C(NHCOCH3)CO2R ' are treated with H-2 (1 atm) and (R)-6(+) PF6- or (S)-12(+) PF6- (0.5 mol%) in THF at room temperature. Protected amino acids are obtained in 70-98% yields and 93-82% ee [(R)-6(+)PF(6)(-)] or 72-60% ee [(S)-12(+) PF6-]. Pressure and temperature effects are defined, and turnover numbers of > 1600 are realized.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/04/20 alle ore 03:05:14