Showing papers by "Hiroaki Sasai published in 2003"
114 citations
TL;DR: Ti-BINOLate complex generated from the obtained monolayer-protected Au cluster (MPC) promoted catalytic asymmetric alkylation of benzaldehyde with Et(2)Zn to afford the adduct in up to 98% yield with 86% ee.
56 citations
47 citations
TL;DR: Polymer-supported bisBINOL ligands were successfully utilized for the immobilization of multicomponent asymmetric catalysts in the Michael reaction of 2-cyclohexen-1-one with dibenzyl malonate affording the adduct in 91% yield with 96% ee.
41 citations
TL;DR: In this article, the authors described the immobilization of chiral lanthanum and/or ytterbium complexes using polymer-support and showed that the heterogeneous catalysts obtained promote the enantioselective epoxidation of α,β-unsaturated ketones affording the products in good yields with high enantiomeric excess.
Abstract: The immobilization of chiral lanthanum and/or ytterbium complexes using polymer-support is described. The heterogeneous catalysts obtained promote the enantioselective epoxidation of α,β-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.
19 citations
TL;DR: In this article, the ability of the lanthanoid complexes generated with polymeric BINOL ligands in promoting the catalytic asymmetric epoxidation of chalcone and benzalacetone was explored.
Abstract: 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 PPh3O the catalysts afforded the product epoxides in good yield with modest enantioselectivity. The heterogeneous nature of these catalysts facilitates the recovery and reuse.
17 citations
TL;DR: The first synthesis of spiro bis(pyrazole) ligands, 2.2',4,4'-tetrahydro-6,6'-spirobi[5H-cycopentapyrazole] (la) and 2,2'-dibenzyl-2,2', 4,4-tetrahedro -6, 6'-SPIRObi[1] (1b) was achieved.
Abstract: The first synthesis of spiro bis(pyrazole) ligands, 2,2',4,4'-tetrahydro-6,6'-spirobi[5H-cycopentapyrazole] (la) and 2,2'-dibenzyl-2,2',4,4'-tetrahydro-6,6'-spirobi[5H-cycopentapyrazole] (1b) was achieved. The applicationof spiro bis(pyrazole) ligand to asymmetric catalysis was also examined.
13 citations
TL;DR: New chiral bis(isoxazoline) ligands bearing a spiro[5.5]undecane skeleton were designed and synthesized in five steps from diethyl malonate and showed a coordinating ability to Cu(II) as chiral ligands.
11 citations
TL;DR: (2S, 3S)-2-Nitro-5-phenyl-1, 3-pentanediol as mentioned in this paper, 3-Phenylpropanal.
Abstract: (2S, 3S)-2-Nitro-5-phenyl-1, 3-pentanediol
R 3-Phenylpropanal
Nitroethanol
P (2S, 3S)-2-Nitro-5-phenyl-1, 3-pentanediol
Keywords:
lanthanum-lithium-(R)-BINOL complex (LLB);
chiral auxiliaries and catalysts;
organometallic compounds, lanthanum;
organometallic compounds, lithium;
metalation reactions, lanthanum;
alcohols, substituted;
nitro compounds;
addition, to CO;
addition, to CCCO and COCN;
enantiomeric excess (EE) determinations, by HPLC;
table;
asymmetic aldol reaction
8 citations
TL;DR: The bisoxazoline ligands were found to be essential to promote the cyclization of alkenyl alcohol and accelerated the Pd(II)-catalyzed Wacker-type cyclization as mentioned in this paper.
Abstract: 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.
6 citations
TL;DR: In this article, the synthesis of spiro bis-pyridinium and bis-quinolinium salts was achieved in three steps via intramolecular N-alkylation.
Abstract: Syntheses of novel spiro bis-pyridinium and bis-quinolinium salts have been achieved in three steps via intramolecular N-alkylation.
TL;DR: The bisoxazoline ligands were found to be essential to promote the cyclization of alkenyl alcohol and accelerated the Pd(II)-catalyzed Wacker-type cyclization.
Abstract: 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.