[CpRu((R)-Binop-F)(H2O)][SbF6], a New Fluxional Chiral Lewis Acid Catalyst: Synthesis, Dynamic NMR, Asymmetric Catalysis, and Theoretical Studies

Article Article scientifique Article [CpRu((R)-Binop-F)(H2O)][SbF6], a New Fluxional Chiral Lewis Acid Catalyst: Synthesis, Dynamic NMR, Asymmetric Catalysis, and Theoretical Studies eng 2004 author Alezra Valérie Camille Viviane 525217 author Bernardinelli Gérald Hugues 24765 author Corminboeuf Anne-Clémence 502754 author Frey Urban author Kundig Ernst Peter 26401 author Merbach André E. author Saudan Christophe M. author Viton Florian 126549 author Weber Jacques 25279 4843-4853 10.1021/ja0374123 0002-7863 http://pubs.acs.org/cgi-bin/article.cgi/jacsat/2004/126/i15/pdf/ja0374123.pdf The C[2]-symmetric electron-poor ligand (R)-BINOP-F (4) was prepared by reaction of (R)-BINOL with bis(pentafluorophenyl)-phosphorus bromide in the presence of triethylamine. The iodo complex [CpRu((R)-BINOP-F)(I)] ((R)-6) was obtained by substitution of two carbonyl ligands by (R)-4 in the in situ-prepared [CpRu(CO)[2]H] complex followed by reaction with iodoform. Complex 6 was reacted with [Ag(SbF[6])] in acetone to yield [CpRu((R)-BINOP-F)(acetone)][SbF[6]] ((R)-7). X-ray structures were obtained for both (R)-6 and (R)-7. The chiral one-point binding Lewis acid [CpRu((R)-BINOP-F)][SbF[6]] derived from either (R)-7 or the corresponding aquo complex (R)-8 activates methacrolein and catalyzes the Diels−Alder reaction with cyclopentadiene to give the [4 + 2] cycloadduct with an exo/endo ratio of 99:1 and an ee of 92% of the exo product. Addition occurs predominantly to the methacrolein C[α]-Re face. In solution, water in (R)-8 exchanges readily. Moreover, a second exchange process renders the diastereotopic BINOP-F phosphorus atoms equivalent. These processes were studied by the application of variable-temperature [1]H, [31]P, and [17]O NMR spectroscopy, variable-pressure [31]P and [17]O NMR spectroscopy, and, using a simpler model complex, density functional theory (DFT) calculations. The results point to a dissociative mechanism of the aquo ligand and a pendular motion of the BINOP-F ligand. NMR experiments show an energy barrier of 50.7 kJ mol[-1] (12.2 kcal mol[-1]) for the inversion of the pseudo-chirality at the ruthenium center. Dewey 540 36 Département de chimie organique 141 38 Département de chimie physique 142 false 685 Groupe Weber Journal of the American Chemical Society 126 15 a214510f-6128-498a-b324-91b859743c21 Article (Published version) Public file1.pdf 707405 application/pdf Vignette Public file1 12426 image/png openAccess Faculté des sciences / Section de chimie et biochimie / Département de chimie organique Faculté des sciences / Section de chimie et biochimie / Département de chimie physique

Title	Published in	Year	Views	Downloads

[CpRu((R)-Binop-F)(H2O)][SbF6], a New Fluxional Chiral Lewis Acid Catalyst: Synthesis, Dynamic NMR, Asymmetric Catalysis, and Theoretical Studies	Journal of the American Chemical Society	2004	781	1,151
[(Indenyl)Ru(biphop-F)]+: A Lewis Acid Catalyst That Controls both the Diene and the Dienophile Facial Selectivity in Diels-Alder Reactions	Angewandte Chemie	2001	628	4

Archive ouverte UNIGE

Alezra, Valérie Camille Viviane