Toure ´and Hall Scheme 6. Synthesis of trans-Jasmonic Acid Using a Noyori-type 3CR, by Yamamoto and Co-workers 23 Scheme 7. Synthesis of Indanomycin Using a Noyori-type 3CR, by Burke and Co-workers 25 Scheme 8. Synthesis of Incarvilline and Incarvine Using a Noyori 3CR, by Kibayashi and Co-workers 26,28

No abstract

We report the effect of metal-island size variation in nanoparticle-enhanced photodetectors. Nanoparticle size was controlled by varying the deposition and annealing conditions used to produce the metal-island films. Increasing the size of silver-island particles fabricated onto 165 nm thick silicon-on-insulator (SOI) photodetectors resulted in a dramatic increase in the observed photocurrent. A nearly factor-of-20 photocurrent enhancement was observed for light of wavelength 800 nm, a significant improvement over previously reported results. The improvement is linked to two physical effects: the increased scattering efficiency of the larger nanoparticles and a qualitative change in the resonance characteristics of the metal-island film due to radiative coupling to the SOI waveguide modes.

This study describes a new class of carbohydrate-binding boronic acids. ortho-Hydroxymethyl phenylboronic acid (boronophthalide) was shown to be superior to the well-established dialkylamino ("Wulff-type") analogues, and it is more soluble in aqueous solvents. The most significant finding in this work is the surprising ability of ortho-hydroxyalkyl arylboronic acids to complex model glycopyranosides under physiologically relevant conditions. These boronic acid units appear to complex hexopyranosides mainly using their 4,6-diol. This behavior is significant because a majority of cell-surface glycoconjugates present free 4,6-diols. Thus, conjugatable forms of these boronic acids could be used in the design of oligomeric receptors and sensors to exploit multivalency effects. Such receptors could dramatically expand the potential of boronic acids toward the selective recognition of cell-surface glycoconjugates.

No abstract

We report the degree to which the resonances associated with metal island films can be used to enhance the sensitivity of very thin semiconductor photodetectors. The island films can couple incident light into the waveguide modes of the detector, resulting in increased absorption. To characterize the coupling, silver-, gold-, and copper-island layers were formed on the surface of a thin-film photodetector fabricated in the 0.16 μm thick silicon layer of a silicon-on-insulator (SOI) wafer. The copper islands gave the best result, producing more than an order of magnitude enhancement in the photocurrent for light of wavelength 800 nm. The enhancements appear to be due primarily to coupling between the metal island resonances and the waveguide modes supported by the SOI structure.

Taming carboxylic acids: ortho‐Iodo‐ and ortho‐bromophenylboronic acids are exceptional organocatalysts in atom‐economical amidations between free carboxylic acids and amines, including functionalized ones, and can also provide LUMO‐lowering activation in [4+2] cycloadditions of α,β‐unsaturated carboxylic acids.

The simplicity, efficiency and generality of the transition-metal-catalysed Suzuki-Miyaura cross-coupling reaction has led to its application in the preparation of a wide variety of organic compounds. Cross-coupling of alkylboron derivatives, however, remains a major challenge, in particular with regard to stereochemical control. Here, we describe the preparation and reaction of highly optically enriched 1,1-diboron compounds. A catalytic asymmetric conjugate borylation of β-boronylacrylates provided geminal diboronate products that feature two distinct boronyl units, in 99% enantiomeric excess. Chemoselective cross-coupling of one-boronyl unit, a trifluoroborate salt, occurred stereospecifically via inversion of its configuration to generate enantioenriched benzylic or allylic boronates. The difficult transmetallation in the Suzuki-Miyaura catalytic reaction cycle is believed to be facilitated by a stabilization effect from the second boronyl unit, and internal coordination by the oxygen of the proximal carboxyester. We also explored subsequent functionalization of the second boronyl unit.