Hisanori Ueki
University of Oklahoma
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Featured researches published by Hisanori Ueki.
Journal of the American Chemical Society | 2009
Vadim A. Soloshonok; Trevor K. Ellis; Hisanori Ueki; Taizo Ono
This work has demonstrated that a previously unexplored approach to separation of enantiomers via formation of diastereomeric derivatives with three stereogenic centers has obvious practical potential and deserves further systematic study. The design reported here is based on the unusual application of a configurationally unstable stereogenic nitrogen, which plays a key role in setting up the stereochemical match between the three stereogenic centers in the corresponding products.
Journal of the American Chemical Society | 2011
Pothiappan Vairaprakash; Hisanori Ueki; Kentaro Tashiro; Omar M. Yaghi
The Merrifield solid-phase peptide synthesis technique has been adapted to the synthesis of homo- and heterometallic metal−organic complex arrays (MOCAs). A terpyridine-appended and Fmoc-protected L-tyrosine derivative was metalated with Pt(II), Rh(III), or Ru(II) ions in solution and sequentially coupled at the surface of functionalized polymeric resin to give a metal complex triad (Rh−Pt−Ru), tetrad (Ru−Rh−Pt−Pt), pentad (Rh−Pt−Ru−Pt−Rh), and hexad (Rh−Pt−Ru−Pt−Rh−Pt) with specific metal sequence arrangements. These were cleaved from the resin, and their character was confirmed by mass spectrometry.
Tetrahedron Letters | 2003
Trevor K. Ellis; Collin H. Martin; Hisanori Ueki; Vadim A. Soloshonok
Ni(II)-complex derived from glycine Schiff base with 2-[N-(α-picolyl)amino]benzophenone (PABP) was found to be an ideal equivalent of nucleophilic glycine in the reactions with various alkyl halides affording an efficient, generalized and practically useful method for preparing symmetrically α,α-disubstituted α-amino acids.
Helvetica Chimica Acta | 2002
Vadim A. Soloshonok; Hisanori Ueki; Changchun Jiang; Chaozhong Cai; Victor J. Hruby
In this study, we developed a new protocol for the preparation of the chiral 3-[(E)-enoyl]-1,3-oxazolidin-2-ones under the ultimately simple reaction conditions starting with the corresponding enoyl chlorides and 1,3-oxazolidin-2-ones with Et3N/LiCl at room temperature. The method generally allows efficient preparation of various derivatives regardless of the steric and electronic nature of the substituents on both the enoyl or the oxazolidinone sites. Excellent yields, combined with the simplicity of the experimental procedures, render the present method immediately useful for preparing the target compounds.
Tetrahedron | 2003
Hisanori Ueki; Trevor K. Ellis; Masood A. Khan; Vadim A. Soloshonok
Abstract We have demonstrated that the readily available amido–keto compounds 5 , with prearranged carbonyl and glycine moieties, under strongly basic conditions easily undergo complete and highly diastereoselective cyclization, affording a generalized and practical access to the conformationally constrained phenylserine derivatives 4 . High chemical yields, virtually complete diastereoselectivity combined with the operational convenience of the experimental procedures render this method useful for preparation of these diastereomerically pure derivatives.
Organic Letters | 2009
Hisanori Ueki; Vadim A. Soloshonok
The presented results and the available literature data convincingly suggest that there is a new sterically driven mechanism for the formation of supramolecular helicity in the solid state. This mechanism requires the presence of sterically bulky groups, such as tert-butyl, for which the spiral arrangement in uninterrupted hydrogen-bonding chains, serving as an axis for helical structure and maximizing the repulsive stereochemical interactions, provide for the most efficient, spatially economical accommodation of these groups in a crystallographic unit cell.
Journal of Physical Chemistry A | 2010
Hisanori Ueki; Garry Chapman; Michael T. Ashby
The mechanism of oxidation of ArSO(2)(-) (PhSO(2)(-) and 5-sulfinato-2-nitrobenzoic acid = TNBO(2)(1-/2-)) with HOCl/OCl(-) has been investigated using the kinetic method. In contrast to previous reports for PhSO(2)(-) (for which it was suggested that OCl(-) and not HOCl was the reactant), the reaction proceeds through a conventional pathway: nucleophilic attack by ArSO(2)(-) on HOCl with concomitant Cl(+) transfer to give a sulfonyl chloride intermediate (ArSO(2)Cl), which we have identified spectrophotometrically. Remarkably, the rate constant for the reaction of HOCl with ArSO(2)(-) is on the order of 10(9) M(-1) s(-1), larger than the rate constants for corresponding thiolates, and is nearly diffusion-controlled. In contrast, the rate constant for the reaction of OCl(-) with ArSO(2)(-) is approximately 7 orders of magnitude smaller.
Beilstein Journal of Organic Chemistry | 2012
Vadim A. Soloshonok; Jose Luis Acena; Hisanori Ueki; Jianlin Han
Summary We describe herein the design and synthesis of asymmetric, pentadentate ligands, which are able to coordinate to Ni(II) cations leading to quasi-diastereomeric complexes displaying two new elements of chirality: stereogenic axis and helix along with configurational stabilization of the stereogenic center on the nitrogen. Due to the stereocongested structural characteristics of the corresponding Ni(II) complexes, the formation of quasi-diastereomeric products is highly stereoselective providing formation of only two, (R a*,M h*,R c*) and (R a*,P h*,R c*), out of the four possible stereochemical combinations. The reversible quasi-diastereomeric transformation between the products (R a*,M h*,R c*) and (R a*,P h*,R c*) occurs by intramolecular trans-coordination of Ni–NH and Ni–O bonds providing a basis for a chiral switch model.
Journal of Sulfur Chemistry | 2009
Hisanori Ueki; Garry Chapman; Michael T. Ashby
An efficient method for synthesizing the sulfenic acid derivative of 5-mercapto-2-nitrobenzoic acid in aqueous medium is described. The electronic spectrum is reported (λmax=490 nm, ϵ=11, 600 M−1 cm−1).
Journal of the American Chemical Society | 2007
Vadim A. Soloshonok; Hisanori Ueki; Manabu Yasumoto; Shekar Mekala; Jennifer S. Hirschi; Daniel A. Singleton