Y. Shimizu 교수

Copper-catalyzed difunctionalization of unactivated carboncarbon multiple bonds involving a carboncarbon bond formation process is reviewed. Carboamination, carbooxygenation, carboboration, and other difunctionalization reactions of alkenes, alkynes, and allenes are described.

Key to success: The first catalytic asymmetric total synthesis of ent-hyperforin (see picture) was accomplished by using a Diels–Alder reaction promoted by a chiral cationic iron catalyst (A; 96 % ee, d.r.>33:1), a diastereoselective Claisen rearrangement (B; 12:1 selectivity), an intramolecular aldol reaction (C), and a vinylogous Pummerer rearrangement (D) as key steps. Naturally occurring polycyclic polyprenylated acylphloroglucinols (PPAPs: Scheme 1) commonly have a highly substituted bicycl

We report copper(I)-catalyzed enantio- and diastereodivergent borylative coupling of styrenes and imines to produce enantiomerically-enriched α,β-dibranched γ-boryl amine derivatives. Each of the four possible stereoisomers of the products, derived from the two contiguous stereocenters, was selectively accessible by choosing a proper chiral ligand for the copper catalyst. This method, which combines catalyst-controlled stereodivergency and constitutional divergency derived from the lynchpin moti

We describe herein the asymmetric synthesis of α-allyl carboxylic acids containing an α-quaternary stereocenter by a chiral hybrid catalyst system comprising palladium and boron complexes. The reaction proceeded through palladium-catalyzed ionization of α,α-disubstituted O-allyl esters for the generation of chiral π-allyl palladium complex as an electrophile, boron-catalyzed enolization of the carboxylate part for the generation of chiral α,α-disubstituted carboxylic acid-derived enolates as a n

We report recent results of a WIMP dark matter search experiment using 310 g of CaF2(Eu) scintillator at Kamioka Observatory. We chose a highly radio-pure crystal, PMTs and radiation shields, so that the background rate decreased considerably. We derived limits on the spin dependent WIMP-proton and WIMP-neutron coupling coefficients, ap and an. The limits excluded a part of the parameter space allowed by the annual modulation observation of the DAMA NaI experiment.

A hybrid medaka between Oryzias latipes and O. curvinotus spawns diploid eggs. We examined the cytological mechanisms of diploid egg formation in this hybrid. Oocytes in the hybrid passed through the first and second meiotic divisions and excluded two polar bodies, associated with reduction of the DNA content in oocytes. Each germinal vesicle in vitellogenic oocytes of the hybrid had 48 chromosomes with bivalent chiasmata, precisely twice the number of chromosomes in normal oocytes. These result

Stay active: Allylcopper species can be generated in situ through catalytic intramolecular oxycupration of allenic alcohol. The allylcopper can react with various aldehydes and a ketone to give 1H-isochromene derivatives in an enantioselective manner (see scheme; HMPA=hexamethylphosphoramide, THF=tetrahydrofuran). The protocol is atom-economical, highly regioselective, stereoconvergent, and tolerant to free hydroxy groups.

In the hybrid medaka between Oryzias latipes and O. curvinotus, the testicular structure, including an efferent duct, seminiferous tubules, and testicular cysts, was similar to that of the parent fishes, indicating that gonadal development during embryogenesis proceeds normally. The hybrid fish had spermatogonia, spermatocytes, and spermatid-like cells in the cyst. Sperm-like cells with a condensed nucleus and elongated flagellum were released into an efferent duct. However, measurement of DNA c