荒井 孝義

Confinement of KI nanocrystals in nanoscale pores of single wall carbon nanohorn (SWCNH) and activated carbon fiber (ACF) below 0.1 MPa induces the formation of high pressure phase solid, although compression under 1.9 GP is necessary for formation of the high pressure phase. Also formation of sulfur-atomic chain crystal having metallic nature is found in the single wall carbon nanotube (SWCNT) and double wall carbon nanotube (DWCNT) below 0.1 MPa, although mettalic sulfur needs compression by more than 90 Gpa in the bulk phase. This remarkably strong compression effect of carbon nanospaces was applied to organic synthesis. Organic synthetic reaction, which occurs only above high pressure of 1GPa without nanopore systems, efficiently progresses in a glass flask under an atmospheric pressure.

The direct approach: A new high-throughput screening system for analyzing the asymmetric induction in catalytic enantioselective synthesis couples solid-phase reactions with a circular dichroism detection system (see picture). Thus, direct monitoring of asymmetric induction without the need for purification or chromatographic analysis is obtained. (Figure Presented). © 2006 Wiley-VCH Verlag GmbH &amp Co. KGaA.

A catalytic allyl-transfer reaction from tertiary homoallylic alcohols to aldehydes was achieved using dibutyltin oxide as a catalyst in toluene under reflux conditions. Various secondary homoallylic alcohols were prepared in high yield (up to 99%). When β-alkylated tertiary homoallylic alcohols were used, branched products were exclusively obtained. © Georg Thieme Verlag Stuttgart.

Asymmetric protonation of lithium enolates was examined using commercially available amino acid derivatives as chiral proton sources. Among the amino acid derivatives tested, N beta-L-aspartyl-L-phenylalanine methyl ester was found to cause significant asymmetric induction in the protonation of lithium enolates. The enantiomeric excess (up to 88% ee) of the products obtained in the presence of a catalytic amount of the chiral proton source was higher than those obtained in the stoichiometric reaction.

Pulse saturation transfer (PST)/MAS was highly effective for enhancing a magic angle spinning (MAS) C-13 NMR of the inter-mobile region of polymer supported organic compounds. Direct monitoring of solid-phase synthesis on non-destructed Syn-Phase lantern was demonstrated using a 7 mm probe on the C-13 PST/MAS NMR study. (c) 2006 Elsevier Ltd. All rights reserved.

A catalytic asymmetric protonation of trimethylsilyl enolates was achieved using a 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP)-silver(I) fluoride complex as a chiral catalyst in a mixed solvent consisting of dichloromethane and methanol. Various nonracemic ketones possessing a tertiary asymmetric carbon at the a-position were prepared with high enantioselectivity up to 99 % ee.

A novel Mannich-type reaction of alkenyl trichloroacetates with aldimines has been realized by using dibutyltin dimethoxide as a catalyst, which is regenerated by addition of methanol. A three-component coupling reaction of aldehydes, primary ammines, and alkenyl trichloroacetates has been also efficiently achieved. These procedures can provide a variety of beta-amino ketones not only from aromatic aldehydes but also from alpha,beta-unsaturated aldehydes mainly with syn-selectivity in high yields up to 99%.

A chiral nitrogen-tethered bis (imidazoline) ligand (Nb-imidazoline) was newly designed and synthesized in a divergent strategy. Thus, a single coupling reaction of primary amine with two molecules of chloromethylated imidazoline provided the Nb-imidazoline. The copper(II) triflate complex of Nb-imidazoline catalyzed a trans-selective cyclopropanation of styrene with ethyl diazoacetate to give the adduct in high chemical yield with good enantiomeric excess up to 83%.

A Barbier-type propargylation of aldehydes with (3-bromoprop-1-ynyl)trimethylsilane has been achieved using reactive barium as a low-valent metal in THE This process is effective also for obtaining the desired homopropargylic alcohols in high yields from the corresponding ketones including enolizable ketones such as cyclopent-2-enone.

Silver lining: A catalytic enantioselective protonation of trimethylsilyl enolates uses a binap/silver(I) fluoride complex as a chiral catalyst in a mixture of dichloromethane and methanol (see scheme). Various ketones with tertiary asymmetric carbon centers at the α position can be prepared with high enantioselectivities. © 2005 Wiley-VCH Verlag GmbH &amp Co. KGaA, Weinheim.

Systematic and quantitative measurements of the roles of stereochemistry and skeleton-dependent conformational restriction were made using multidimensional screening. We first used diversity-oriented synthesis to synthesize the same number (122) of [10.4.0] bicyclic products (B) and their corresponding monocyclic precursors (M). We measured the ability of these compounds to modulate a broad swath of biology using 40 parallel cell-based assays. We analyzed the results using statistical methods that revealed illuminating relationships between stereochemistry, ring number, and assay outcomes. Conformational restriction by ring-closing metathesis increased the specificity of responses among active compounds and was the dominant factor in global activity patterns. Hierarchical clustering also revealed that stereochemistry was a second dominant factor; whereas the stereochemistry of macrocyclic appendages was a determinant for bicyclic compounds, the stereochemistry of the carbohydrates was a determinant for the monocyclic compounds of global activity patterns. These studies illustrate a quantitative method for measuring stereochemical and skeletal diversity of small molecules and their cellular consequences.

Disulfides bearing (R)-1,1'-bi-2-naphthol ((R)-BINOL) moieties at each terminal position have been successfully introduced on the surface of Au cluster. Ti-BINOLate complex generated from the obtained monolayer-protected Au cluster (MPC) promoted catalytic asymmetric alkylation of benzaldehyde with Et2Zn to afford the adduct in up to 98% yield with 86% ee. After completion of the reaction, the BINOL-functionalized MPC was easily recovered.

[GRAPHICS]Polymer-supported bisBINOL ligands were successfully utilized for the immobilization of multicomponent asymmetric catalysts. The polymer-supported Al-Li-bis(binaphthoxide) (ALB) catalyst was more effective than the dendrimer-supported ALB in the Michael reaction of 2-cyclohexen-1-one with dibenzyl malonate affording the adduct in 91% yield with 96% ee. The polymer was also effective for the immobilization of a mu-oxodititanium complex that promoted carbonyl-ene reaction of ethyl glyoxalate with alpha-methyl styrene to provide the adduct with up to 98% ee.

Combination of Pd(OCOCF3)(2) and (M,S,S)-iPr-SPRIX ligand promoted the intramolecular cyclization of 2-alkynoates very effectively to form alpha-methylene-gamma-butyrolactones in good yields with up to 92% ee. (C) 2003 Elsevier Science Ltd. All rights reserved.

The immobilization of chiral lanthanum and/or ytterbium complexes using polymer-support is described. The heterogeneous catalysts obtained promote the enantioselective epoxidation of alpha,beta-unsaturated ketones affording the products in good yields with high enantiomeric excess. The catalysts were easily separated from the products by washing with ether and the recovered catalysts promote the enantioselective epoxidation reaction effectively maintaining the high level of enantioselectivity obtained during the first run. (C) 2003 Elsevier Science Ltd. All rights reserved.

The ability of the lanthanoid complexes generated with polymeric BINOL ligands in promoting the catalytic asymmetric epoxidation of chalcone and benzalacetone was explored. In the presence of additives like water and PPh3=O the catalysts afforded the product epoxides in good yield with modest enantioselectivity. The heterogeneous nature of these catalysts facilitates the recovery and reuse. (C) 2002 Elsevier Science B.V. All rights reserved.

Synthesis of two kinds of new bis(isoxazoline) ligand, achiral 2,2'-bis(isoxazolinyl)propane and (R)-2,2'-bis(isoxazolinyl)-1,1'-binaphthyl bearing an axial chirality is described. Both of the bis(isoxazoline) ligands accelerated the Pd(II)-catalyzed Wacker-type cyclization of alkenyl alcohol. The isoxazoline ligands were found to be essential to promote the cyclization.

New chiral bis(isoxazoline) ligands bearing a spiro[5.5]undecane skeleton were designed and synthesized in five steps from diethyl malonate (3). These ligands showed a coordinating ability to Cu(II) as chiral ligands. A complex of (+)-(M*,S*,R*)-[5.5]-SPRDC 2b and Cu(OTf)(2) catalyzed the conjugate addition of diethylzine to 2-cyclohexenone (8) to give (S)-3-ethyl-cyclohexanone (9) in 93% yield with 54% ee. (C) 2002 Wiley-Liss, Inc.

The highly ligand acceleration effect of spiro bis(isoxazoline) ligand (SPRIX) on the Pd(II)-catalyzed intramolecular aminocarbonylation of alkenyl amine derivatives was realized. Furthermore, the chiral Pd(II)-SPRIX catalyst accomplished the first enantioselective intramolecular aminocarbonylation. The reaction of N-(2,2-dimethyl-pent-4-enyl)-p-toluenesulfonamide in the presence of Pd(II)-SPRIX catalyst and p-benzoquinone in methanol under a carbon monoxide atmosphere afforded [4,4-dimethyl-1-(p-toluene-sulfonyl)-pyrrolidin-2-yl]-acetic acid methyl ester in good yield with moderate enantioselectivity. (C) 2003 Elsevier Science Ltd. All rights reserved.