A Convenient Synthesis of (S)-H4-BINOL and Its Derivatives via Hydrogenation of Monoesters of BINOL
摘要:
A new multigram synthesis of chiral (S)-H-4-BINOL and its derivatives in moderate to high yield (up to 83% total yield) via monoesterification of (S)-BINOL, hydrogenation, and saponification reaction was described. The two new monomethylated (S)-H-4-BINOL obtained may be useful materials in asymmetric catalysis.
Discovery of Exceptionally Efficient Catalysts for Solvent-Free Enantioselective Hetero-Diels−Alder Reaction
摘要:
Combinatorial coordination chemistry strategy combined with high-throughput screening techniques has been successfully applied to engineering practical enantioselective catalysts for asymmetric hetero-Diels-Alder reaction. The reaction of Danishefsky's diene with a variety of aldehydes can be carried out with 0.1-0.005 mol % of H4-BINOL/Ti/H4-BINOL or H4-BINOL/Ti/H8-BINOL catalysts at room temperature under solvent- and MS-free conditions to afford dihydropyrone derivatives with up to quantitative yield and 99.8% ee.
An object of the present invention is to provide a method for manufacturing an optically active menthol having fewer steps, which generates less environmentally polluting waste because a catalytic reaction is involved in all of the steps, and is capable of saving a production cost. The present invention relates to a method for manufacturing an optically active menthol, including the following steps: A-1) asymmetrically hydrogenating at least one of geranial and neral to thereby obtain an optically active citronellal, B-1) conducting a ring-closure reaction of the optically active citronellal in the presence of an acid catalyst to thereby obtain an optically active isopulegol, and C-1) hydrogenating the optically active isopulegol to thereby obtain an optically active menthol.
[EN] ALUMINIUM COMPLEXES AND USE THEREOF AS A CATALYST IN INTRAMOLECULAR RING CLOSURE REACTIONS<br/>[FR] COMPLEXES D'ALUMINIUM ET LEUR UTILISATION EN TANT QUE CATALYSEUR DANS DES RÉACTIONS INTRAMOLÉCULAIRES DE FERMETURE DE CYCLE
申请人:TAKASAGO PERFUMERY CO LTD
公开号:WO2010071227A1
公开(公告)日:2010-06-24
To provide a process for increasing the proportion of an optical isomer of not only a compound having a closed ring but also a compound not having a closed ring when an optical isomer mixture of a compound having both a formyl group and a double bond capable of causing a carbonyl-ene ring closing reaction in the same molecule is subjected to a ring closing reaction. A process for increasing the proportion of an optical isomer characterized by subjecting an optical isomer mixture of a compound having both a formyl group and a double bond capable of causing a carbonyl-ene ring closing reaction in the same molecule to a ring closing reaction in the presence of a predetermined aluminum complex represented by the general formula: [Al2(L1)n(L2)3-n]m.
A catalyst for obtaining isopulegol of high diastereoselectivity by highly selective cyclization reaction of citronellal is provided. The present invention relates to an organoaluminum compound obtained by reacting at least one organoaluminumoxy compound selected from the group consisting of chain aluminoxanes, cyclic aluminoxanes and bis(dialkylaluminumoxy)alkylboranes, with at least one hydroxy compound selected from the group consisting of diarylphenols, bis(diarylphenol) compounds, biaryldiols, dimethanols and silanols.
Provided is a process in which cyclization of a compound having, in a molecule, a formyl group and a double bond which allow carbonyl-ene cyclization, the compound existing as a mixture of optical isomers thereof, increases the ratio of a particular optical isomer not only in a cyclized compound, but also in an unreacted compound. The process comprises performing, in the presence of a specified aluminum complex represented by the general formula: [Al
2
(L
1
)
n
(L
2
)
3-m
]
m
, cyclization of a compound having, in a molecule, a formyl group and a double bond which allow carbonyl-ene cyclization, the compound existing as a mixture of optical isomers thereof, to increase the ratio of a particular optical isomer.
Synthesis of modified H4-BINOL ligands and their applications in the asymmetric addition of diethylzinc to aromatic aldehydes
作者:Yong-Na Lu、Qun-Sheng Guo、Fu-Yong Jiang、Jin-Shan Li
DOI:10.1016/j.tetasy.2006.06.042
日期:2006.7
Two new ligands (S,S)-3-(1,1'-bi-2-naphthol-3-yl)-5,6,7,8-tetrahydro-1,1'-bi-2-naphthol [(S,S)-1] and (S)-3-(morpholin-4-yl-methyl)-H-4-BINOL [(S)-2] have been synthesized via Suzuki cross-coupling reaction and a Mannich-type reaction, respectively. In the presence of titanium tetraisopropoxide, 0.8 mol% of ligand (S,S)-1 catalyzed the asymmetric addition of diethylzinc to aromatic aldehydes in good yield and with high enantioselectivity. (c) 2006 Elsevier Ltd. All rights reserved.