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.
Oxidative coupling of highly coordinating metal phenolates promoted by FeCl3 afforded variously substituted symmetric 2,2′-dihydroxy biaryls in good yield and high regiochemical control.
[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.