Generally used and highly reactive RMgBr reagents were effectively deactivated by bis[2-(N,N-dimethylamino)ethyl] ether and then were employed in the highly enantioselective addition of Grignard reagents to aldehydes. The reaction was catalyzed by the complex of commercially available (S)-BINOL and Ti(O'Pr-)(4) under mild conditions. Compared with the other observed Grignard reagents, alkyl Grignard reagents showed higher enantioselectivity and they achieved >99% ee.
A finite width dielectric-metal-dielectric (DMD) waveguide placed on a substrate is numerically investigated near the telecom wavelength lambda = 1550 nm by the finite element method. With proper waveguide sizes, the asymmetrical DMD waveguide can support hybrid long-range surface plasmon-polariton modes which have tight field confinement (similar to 700 nm) and long propagation lengths (L> 300 mu m) simultaneously. Compact plasmonic waveguide-ring resonators (WRRs) based on such asymmetrical DMD waveguide show high quality factors compared with dielectric-loaded surface plasmon-polariton, channel plasmon polariton, plasmonic whispering-gallery microcavity, and pure dielectric waveguide cases. (C) 2009 Optical Society of America