Azusa Sato

Synthesis of compounds with juvenile hormone activity—XI : New routes for the stereo-controlled construction of the trisubstituted cis double bond portion of the cecropia juvenile hormones

3-Methylpent-2-cis-enyl bromide (XI) and 4-methylhex-3-cis-enyl bromide (XIX), the key starting materials for the syntheses of the Cecropia juvenile hormones, were synthesized stereospecifically or stereoselectively.

Stereoselective construction of functionalized (Z)-fluoroalkenes directed to depsipeptide isosteres

Abstract Cu(I)-mediated alkyl-transfer reaction of trialkylaluminum (R 3 Al) with ( E )- or ( Z )-4,4-difluoro-5-hydroxyallylic alcohol derivatives proceeded in an SN′-type manner to give the corresponding 2-alkylated ( Z )-4-fluoro-5-hydroxyhomoallylic alcohol derivatives with 2,5- syn - or 2,5- anti selectivity, respectively. Oxidation of the primary hydroxyl group of the product to carboxylic acid was easily achieved without epimerization at the chiral centers.

Enantioselective aromatic Claisen rearrangement

Abstract The development of a highly enantioselective aromatic Claisen rearrangement was achieved by the reaction of catechol mono allylic ethers with chiral boron reagent 1 . This system was also shown to avoid the formation of para rearrangement and abnormal Claisen rearrangement products.

Preparation of difluoro analogs of CCGs and their pharmacological evaluations

All the stereoisomers of 2-(2-carboxy-3,3-difluorocyclopropyl)glycines (F2CCGs) were synthesized in enantiomerically pure forms using (R)-2,3-O-isopropyl-ideneglyceraldehyde as a chiral precursor. L-F2CCG-I, one of the stereoisomers corresponding to an extended form of L-glutamate was found to be a potent agonist for metabotropic glutamate receptors (mGluRs).

Formation of a functionalized cyclobutane ring through the reaction of γ,γ-dialkoxyallylic zirconium species with acrylamide

Abstract The functionalized cyclobutane derivatives could be obtained by the reaction of γ,γ-dialkoxyallylic zirconium species with acrylamide.

1,4-Addition reaction of γ, γ-dialkoxyallylic zirconium species as agem-dialkoxycyclopropyl anion equivalent

Abstract In the presence of a Lewis acid (Et 2 AlCl), γ, γ-dialkoxyallylic zirconium species reacted with α, β-unsaturated- N -acyloxazolidinone to give gem -dialkoxycyclopropane derivatives through 1, 4-addition reaction. Download full-size image

Production of Hydroxyl Radicals and α-dicarbonyl Compounds Associated with Amadori Compound-Cu 2+ Complex Degradation

The chemical properties of Amadori compounds in the presence of transition metal ions were studied, using the analogs 1-deoxy-1- n -butylamino- d -fructose (DBF) and N f -formyl-fructoselysine (fFL). The following characteristics were revealed: (a) DBF combined easily with Cu 2+ (but no other transition metal ions) to form a DBF-Cu 2+ complex in phosphate buffer, pH 7.4; (b) the complex was unstable, and degraded with the release of Cu + during incubation at 37°C; (c) degradation of the complex was associated with the production of hydroxyl radicals by the Fenton reaction and f -dicarbonyl compounds by non-autoxidative degradation; and (d) properties of DBF were similar to those of fFL. The above properties were additionally observed in glycated poly-Lys (GPL). Our findings indicate a novel mechanism for the generation of hydroxyl radicals and f -dicarbonyl compounds from Amadori adducts in the presence of Cu 2+ .

Cu(I)-assisted carboncarbon bond forming reactions of γ,γ-dialkoxyallylic zirconium species: a new versatile homoenolate equivalent of propionate

Abstract In the presence of CuCN, reaction of γ,γ-dialkoxyallylic zirconium species 1 with acyl chloride or allylic phosphates proceeded at the α-position of 1 to give alkanoates 3 after aqueous work-up. The ketene dialkylacetal moiety in the coupling products 2 can be used for further bond forming reaction with electrophiles such as nitrosobenzene, nitrostyrene or trichloroacetylisocyanate.

Enantioselective Claisen rearrangement of difluorovinyl allyl ethers

The enantioselective Claisen rearrangement of difluorovinyl allyl ethers was achieved, for the first time, in moderate to good enantioselectivity using a chiral boron reagent as the Lewis acid.