Catalytic asymmetric alkynylation of carbonyl compounds is one of the most efficient routes for the synthesis of optically active propargylic alcohols, which are useful and versatile building blocks for a variety of functionalized molecules, such as biologically active natural products.[1] In the initial stages of development of this transformation, stoichiometric amounts of metal reagents such as organolithium, organomagnesium, and diorganozinc compounds were used to increase the nucleophilicity of the alkyne and to prevent an undesired retro reaction. [1,2] In terms of atom economy, [3] however, the direct in situ generation of a metal alkynylide species from terminal alkynes using a catalytic amount of the metal reagent is highly desirable. Since the pioneering work by Carreira and co-workers, who utilized catalytic amounts of Zn(OTf) 2 , Nmethylephedrine, and Et 3 N, [4] several efficient methods for the catalytic asymmetric alkynylation of aldehydes have been developed using chiral Zn, [5] In, [6] Cu, [7] and Ru [8] catalysts.[9]In contrast to the substantial progress made with aldehydes, the development of a catalytic asymmetric alkynylation of ketones for the construction of a tetrasubstituted carbon center in an enantioselective manner has had limited success due to low reactivity, difficulty in obtaining enantiofacial differentiation, and the ease of the retro reaction as compared with aldehydes.[10] Jiang et al. succeeded in promoting the asymmetric alkynylation of a-ketoesters with broad substrate scope and high enantioselectivity (up to 94 % ee)[11a] by modifying Carreiras Zn system. [4] Later, Shibasaki and co-workers reported Cu catalysis of trifluoromethyl ketone with up to 52 % ee, [11b] and the Rh catalysis of an a-diketone reported by Chisholm and co-workers gave the product in 5 % yield with 20 % ee.[11c] Although the method of Jiang et al. is useful for accessing chiral propargylic alcohols, there remains much room for improvement because this system requires 20 mol % catalyst loading, 30 mol % of external amine base, and a rather high reaction temperature (70 8C).[11a] Herein, we report the catalytic asymmetric alkynylation of a-ketoester 1 using various aryl-and alkylsubstituted terminal alkynes 2 catalyzed by as little as 3 mol % of C 1 -symmetric Rh/Phebox complexes 3 i and 3 j (Figure 1) to afford the corresponding propargylic alcohols with greater than 99 % ee. Because the acetate ligand on the Rh complex acted as an internal base, the reactions proceeded at 25 8C without any additives. An indanyl substituent on the oxazoline ligand was effective for obtaining high enantioselectivity and, in most cases, the C 1 -symmetric complex gave better results than the C 2 -symmetric complex. The electronic tuning of the Rh complex was achieved by introducing a nitro group at the para position to Rh and greatly improved both the reactivity and selectivity of the reaction. Moreover, the Rh complex had unique chemoselectivity; it selectively reacted with a a-ketoester over an aldehyde, thus allowing...

The ability to simply and economically produce carbon nanotubes (CNTs) with a defined chiral angle is crucial for the exploitation of nanotubes for their electrical properties. We investigate a diverse range of nitrogen sources for their ability to control CNT chiral angle via epitaxial growth from highly ordered catalyst particles. Through the use of in situ mass and infrared spectrometry, we elucidate the mechanism by which these ordered catalyst particles are formed, showing that ammonia is a key intermediate in the process. Subsequently, the direct addition of a small amount of ammonia to an otherwise standard CNT synthesis is shown to be able to form catalyst particles that grow single chiral angle multiwalled carbon nanotubes. Variation in the ammonia concentration clarifies the catalyst restructuring necessary for the epitaxial growth of carbon nanotubes and subsequent chiral angle control. The simple addition of a nitrogen source is an attractive route for chiral angle control; however, the model also suggests further ways to optimize CNT chiral angle distributions as well as to improve CNT and graphene yield and crystallinity. This understanding also explains the action of ammonia in its widely used role in activating catalyst prior to CNT growth. Finally, this work highlights the uses of novel surface geometries that are achievable through multiphase catalysts.

With a view to providing paramedical care within moving vehicles, a telemedicine technique using mobile satellite communication was proposed. With this technique, the diagnosis from a specialist and the emergency care under his/her instructions would be available on the spot without unnecessary delay. The characteristic problems of this technique were identified as: channel capacity, size of the system, reliability of vital sign transmission, real-time operation and electromagnetic interference. Measures against these problems were devised, and their effectiveness was analyzed. A data format was designed and an experimental system was developed. The system can simultaneously transmit a color image, an audio signal, 3 channels ECG and blood pressures from a mobile station to a ground station. It can transmit an audio signal and error control signals from a ground station to a mobile station in a full duplex mode. Fundamental transmission characteristics were measured in a fixed station. Finally, experiments of medical data transmission were conducted with a navigating ship and an aircraft flying an international route. The measured threshold values of C/N(o) to guarantee satisfactory data reception were well below the lower boundary of C/N(o) of the communication link. Consequently, the feasibility of this technique was verified.

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The flocculation method using polymer materials and water solvent was applied to the separation of Nd and Dy. Dy was precipitated preferentially from Dy and Nd mixture solution by poly(allylamine) and adipic acid as flocculation agents. The recovery ratio of Dy was 80%, and the purity of Dy was 76% by optimization of the molar ratio of the amino group of poly(allylamine) to rare-earth metal ions.