S. J. Rettig

Bio: S. J. Rettig is an academic researcher from University of British Columbia. The author has contributed to research in topics: Reactivity (chemistry) & Asymmetric hydrogenation. The author has an hindex of 13, co-authored 34 publications receiving 664 citations.

Stereoselective formation of rhodium and iridium hydrides via intramolecular hydrogen bonding

Abstract: Ir(CH 3 )I(H)[NH(SiMe 2 CH 2 P(i-Pr) 2 ) 2 ] cristallise dans le systeme triclinique avec le groupe d'espace P1 (R=0,040). Rh(H) 2 I[NH(SiMe 2 CH 2 P(i-Pr) 2 ) 2 ] cristallise dans le systeme monoclinique avec le groupe d'espace P2 1 /n (R=0,029). Ir(H) 2 Cl[NH(SiMe 2 CH 2 PPh 2 ) 2 ].CH 3 C 6 H 5 cristallise dans le systeme monoclinique avec le groupe d'espace P2 1 /a (R=0,039)

Synthesis and structure of Pd(II) complexes containing chelating (phosphinomethyl)oxazoline P,N-type ligands; copolymerisation of ethylene/CO

Abstract: The ligands (2-oxazoline-2-ylmethyl)diphenylphosphine (III or PCH2ox) and (2-oxazoline-2-ylmethyl-4,4-dimethyl)diphenylphosphine (IV or PCH2oxMe2) have been used as chelates towards Pd(II) methyl complexes. The complexes [PdMe(Cl)(PCH2ox)] 2a and [PdMe(Cl)(PCH2oxMe2)] 2b were obtained from [PdMe(Cl)(cod)] (cod = cycloocta-1,5-diene) in 83% and 94% yield, respectively, and compared to [PdCl2(PCH2oxMe2)] 1 which was characterised by X-ray diffraction. A series of cationic methyl complexes obtained by chloride abstraction in the presence of MeCN, SMe2, P(OPh)3 or no added donor except the counter ion were prepared in order to evaluate their catalytic performances in ethylene/CO copolymerisation.

Pyrazine and pyridine complexes of copper(II) trifluoromethanesulfonate. Crystal structure of tetrakis(pyridine)bis(trifluoromethanesulfonato-O)copper(II) and magnetic exchange in (pyrazine)bis(trifluoromethanesulfonato-O)copper(II)

Abstract: Cu(py) 4 (CF 3 SO 3 ) 2 cristallise dans le systeme orthorhombique, groupe d'espace Pbcn et sa structure est affinee jusqu'a R=0,046. Coordinat pseudooctaedrique deforme autour de Cu

Asymmetric Catalysis by Architectural and Functional Molecular Engineering: Practical Chemo‐ and Stereoselective Hydrogenation of Ketones

Abstract: Hydrogenation is a core technology in chemical synthesis. High rates and selectivities are attainable only by the coordination of structurally well-designed catalysts and suitable reaction conditions. The newly devised [RuCl(2)(phosphane)(2)(1,2-diamine)] complexes are excellent precatalysts for homogeneous hydrogenation of simple ketones which lack any functionality capable of interacting with the metal center. This catalyst system allows for the preferential reduction of a C=O function over a coexisting C=C linkage in a 2-propanol solution containing an alkaline base. The hydrogenation tolerates many substituents including F, Cl, Br, I, CF(3), OCH(3), OCH(2)C(6)H(5), COOCH(CH(3))(2), NO(2), NH(2), and NRCOR as well as various electron-rich and -deficient heterocycles. Furthermore, stereoselectivity is easily controlled by the electronic and steric properties (bulkiness and chirality) of the ligands as well as the reaction conditions. Diastereoselectivities observed in the catalytic hydrogenation of cyclic and acyclic ketones with the standard triphenylphosphane/ethylenediamine combination compare well with the best conventional hydride reductions. The use of appropriate chiral diphosphanes, particularly BINAP compounds, and chiral diamines results in rapid and productive asymmetric hydrogenation of a range of aromatic and heteroaromatic ketones and gives a consistently high enantioselectivity. Certain amino and alkoxy ketones can be used as substrates. Cyclic and acyclic alpha,beta-unsaturated ketones can be converted into chiral allyl alcohols of high enantiomeric purity. Hydrogenation of configurationally labile ketones allows for the dynamic kinetic discrimination of diastereomers, epimers, and enantiomers. This new method shows promise in the practical synthesis of a wide variety of chiral alcohols from achiral and chiral ketone substrates. Its versatility is manifested by the asymmetric synthesis of some biologically significant chiral compounds. The high rate and carbonyl selectivity are based on nonclassical metal-ligand bifunctional catalysis involving an 18-electron amino ruthenium hydride complex and a 16-electron amido ruthenium species.

Catalytic enantioselective addition to imines.

Abstract: Chiral nitrogen-containing compounds are widely distributed in nature and include many biologically important molecules (Chart 1). In these compounds, the nitrogen-containing units are known to play important roles for their bioactivities. For the synthesis of these chiral nitrogen-containing building blocks, use of imines as electrophiles is the most promising and convenient route.1 While many approaches using chiral imines or chiral nucleophiles have been reported,1 these diastereoselective reactions have some disadvantages. First, the procedures to introduce chiral auxiliaries to substrates and to remove them after the diastereoselective reactions are often tedious. Second, more than stoichiometric amounts of chiral sources are needed to obtain chiral compounds according to these reactions. On the other hand, catalytic enantioselective reactions provide the most efficient methods for the synthesis of chiral compounds,2 because large quantities of chiral compounds are expected to be prepared using small amounts of chiral sources. While much progress has been made recently in catalytic enantioselective reactions of aldehydes and ketones such as aldol,3 allylation,4 Diels-Alder,5 cyanation reactions,6 reduction,1b,2b etc., progress in catalytic enantioselective reactions of imines is rather slow. There are some difficulties in performing catalytic enantioselective reactions of imines. For example, in the cases of chiral Lewis acid promoted asymmetric Shū Kobayashi was born in 1959 in Tokyo, Japan. He studied chemistry at the University of Tokyo and received his Ph.D. in 1988 (Professor T. Mukaiyama). After spending 11 years at Science University of Tokyo (SUT), he moved to Graduate School of Pharmaceutical Sciences, University of Tokyo, in 1998. His research interests include development of new synthetic methods, development of novel catalysts (especially chiral catalysts), organic synthesis in water, solid-phase organic synthesis, total synthesis of biologically interesting compounds, and organometallic chemistry. He received the first Springer Award in Organometallic Chemistry in 1997.

Transition Metal-Catalyzed Enantioselective Hydrogenation of Enamines and Imines

Abstract: Transition metal-catalyzed enantioselective hydrogenation of enamides and enamines is one of the most important methods for the preparation of optically active amines. This review describes the recent developments of highly efficient catalytic asymmetric hydrogenation of enamides, and enamines. It specifically focuses on the substrates because hydrogenation of enamides and enamines is highly dependent on the substrates although the chiral metal catalysts play a significant role.

Metal–Ligand Cooperation

Abstract: Metal-ligand cooperation (MLC) has become an important concept in catalysis by transition metal complexes both in synthetic and biological systems. MLC implies that both the metal and the ligand are directly involved in bond activation processes, by contrast to "classical" transition metal catalysis where the ligand (e.g. phosphine) acts as a spectator, while all key transformations occur at the metal center. In this Review, we will discuss examples of MLC in which 1) both the metal and the ligand are chemically modified during bond activation and 2) bond activation results in immediate changes in the 1st coordination sphere involving the cooperating ligand, even if the reactive center at the ligand is not directly bound to the metal (e.g. via tautomerization). The role of MLC in enabling effective catalysis as well as in catalyst deactivation reactions will be discussed.