Global energy consumption is projected to increase, even in the face of substantial declines in energy intensity, at least 2-fold by midcentury relative to the present because of population and economic growth. This demand could be met, in principle, from fossil energy resources, particularly coal. However, the cumulative nature of CO2 emissions in the atmosphere demands that holding atmospheric CO2 levels to even twice their preanthropogenic values by midcentury will require invention, development, and deployment of schemes for carbon-neutral energy production on a scale commensurate with, or larger than, the entire present-day energy supply from all sources combined. Among renewable energy resources, solar energy is by far the largest exploitable resource, providing more energy in 1 hour to the earth than all of the energy consumed by humans in an entire year. In view of the intermittency of insolation, if solar energy is to be a major primary energy source, it must be stored and dispatched on demand to the end user. An especially attractive approach is to store solar-converted energy in the form of chemical bonds, i.e., in a photosynthetic process at a year-round average efficiency significantly higher than current plants or algae, to reduce land-area requirements. Scientific challenges involved with this process include schemes to capture and convert solar energy and then store the energy in the form of chemical bonds, producing oxygen from water and a reduced fuel such as hydrogen, methane, methanol, or other hydrocarbon species.

/pdf/powering-the-planet-chemical-challenges-in-solar-energy-1kb0jbsg7k.pdf

Powering the planet: Chemical challenges in solar energy utilization

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.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/1521-3773%2820010105%2940%3A1%3C40%3A%3AAID-ANIE40%3E3.0.CO%3B2-5

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

Cyclometalated phosphine-based pincer complexes: Mechanistic insight in catalysis, coordination, and bond activation

Transition-metal-catalyzed addition of heteroatom-hydrogen bonds to alkynes.

This critical review discusses historical and contemporary research in the field of transition metal-catalyzed carbon–hydrogen (C–H) bond activation through the lens of stereoselectivity. Research concerning both diastereoselectivity and enantioselectivity in C–H activation processes is examined, and the application of concepts in this area for the development of novel carbon–carbon and carbon–heteroatom bond-forming reactions is described. Throughout this review, an emphasis is placed on reactions that are (or may soon become) relevant in the realm of organic synthesis (221 references).

Transition metal-catalyzed C–H activation reactions: diastereoselectivity and enantioselectivity

Utilisation de complexes de Rh(I) du type [Rh(diphosphine) (diene)]ClO 4 et [Rh(diphosphine)(S) 4 ]ClO 4 (diphosphine: diphosphine tertiaire chelatant-cis; diene=cyclooctadiene ou norbornadiene; S=solvant). Ces composes sont des catalyseurs actifs de la migration d'hydrogene dans les allylamines secondaires et tertiaires pour donner les (E)-enamines et imines correspondants

Metal-assisted terpenoid synthesis. 7. Highly enantioselective isomerization of prochiral allylamines catalyzed by chiral diphosphine rhodium(I) complexes. Preparation of optically active enamines

Chiral metal complexes. 4. Resolution of racemic tertiary phosphines with chiral palladium(II) complexes. The chemistry of diastereomeric phosphine palladium(II) species in solution

Mechanism of the asymmetric isomerization of allylamines to enamines catalyzed by 2,2'-bis(diphenylphosphino)-1,1'binaphthyl-rhodium complexes

Efficient transfer hydrogenation of alkynes and alkenes with methanol catalysed by hydrido(methoxo)iridium(III) complexes

Selective Formation of Homoleptic and Heteroleptic 2,5-Bis(N-aryliminomethyl)pyrrolyl Yttrium Complexes and Their Performance as Initiators of ε-Caprolactone Polymerization

Kazuhide Tani

Papers

Metal-assisted terpenoid synthesis. 7. Highly enantioselective isomerization of prochiral allylamines catalyzed by chiral diphosphine rhodium(I) complexes. Preparation of optically active enamines

Chiral metal complexes. 4. Resolution of racemic tertiary phosphines with chiral palladium(II) complexes. The chemistry of diastereomeric phosphine palladium(II) species in solution

Mechanism of the asymmetric isomerization of allylamines to enamines catalyzed by 2,2'-bis(diphenylphosphino)-1,1'binaphthyl-rhodium complexes

Efficient transfer hydrogenation of alkynes and alkenes with methanol catalysed by hydrido(methoxo)iridium(III) complexes

Selective Formation of Homoleptic and Heteroleptic 2,5-Bis(N-aryliminomethyl)pyrrolyl Yttrium Complexes and Their Performance as Initiators of ε-Caprolactone Polymerization