Abstract:
PROBLEM TO BE SOLVED: To provide a method enabling to manufacture optically active menthol, desirably L-menthol and racemic menthol in a variety of quantity according to the demand without changing an enantioselective catalyst system and/or without excessively obtaining one of products for need of changing a reaction condition.SOLUTION: A method for producing menthol includes a process (a. 1) of obtaining a citronellal by catalyst-hydrogenation of a neral and/or a geranial, a process (b. 1) of obtaining an isopulegol by cyclizing citronellal in the presence of an acid catalyst, a process (c. 1) of purifying the isopulegol by crystallization, and a process (d. 1) of producing menthol by catalyst-hydrogenation of the isopulegol.
Abstract:
The invention relates to a particularly economic, complete method for producing menthol, especially for the production of optically active, essentially enantiomerically and diastereomerically pure L-menthol and of racemic menthol starting from the commercially accessible, inexpensive parent material citral. The method comprises the following steps: a.1 ) catalytic hydrogenation of neral and/or geranial to form citronellal, b.1 ) cyclisation of citronellal to form isopulegol in the presence of an acidic catalyst, c.1 ) purification of isopulegol by crystallisation and d.1 ) catalytic hydrogenation of isopulegol to form menthol.
Abstract:
The present invention relates to a method for reacting compounds, comprising at least one carbon-carbon or carbon-heteroatom double bond, by 1,2-addition in the presence of a catalyst, comprising at least one transition metal complex having at least two ligands, which each have a pnicogen atom-containing group and at least one functional group enable to form intermolecular, non-covalent bonds, in the presence of a halogenated solvent, which has at least one heteroatom different from halogen. The present invention further relates to a method for producing chiral compounds in the presence of the above-described catalysts and solvents, and to the use of these catalysts in the presence of such solvents.
Abstract:
The present invention relates to phosphine borane compounds comprising imidazol groups, optically active ligands produced using said compounds, transition metal complexes comprising such ligands, and catalyzers comprising said transition metal complexes. The present invention further relates to methods for producing each of the phosphine borane compounds, the optically active ligands, the transition metal complexes, and the catalyzers, as well as the use of the catalyzers for organic transformation reactions. The present invention further relates to a method for producing phosphor compounds comprising imidazol groups and comprising optically active ligands, using phosphine borane compounds comprising imidazol groups.
Abstract:
The invention relates to a method for iodinating aromatic and/or heteroaromatic compounds, characterized in that aromatic compounds are reacted with an iodine source in the presence of at least one base and at least one catalyst containing gold. The invention further relates to catalysts containing gold and a method for producing the same. The invention additionally relates to a method for producing aniline.
Abstract:
The invention relates to imidazole group-containing phosphorus compounds according to general formula (I) or (II), wherein W is phosphorus (P) or phosphite (P=O), to optically active ligands produced while using the same, to transition metal complexes containing said ligands, and to catalysts comprising said transition metal complexes. The invention further relates to the respective methods for producing the phosphorus compounds, the optically active ligands, the transition metal complexes and the catalysts, and to the use of the catalysts for organic transformation reactions.
Abstract:
The present invention relates to a process for asymmetric synthesis in the presence of a chiral catalyst comprising at least one complex of a metal of transition group VIII with ligands capable of dimerization via noncovalent bonds, such catalysts and their use.
Abstract:
The present invention relates to phosphine borane compounds comprising imidazol groups, optically active ligands produced using said compounds, transition metal complexes comprising such ligands, and catalyzers comprising said transition metal complexes. The present invention further relates to methods for producing each of the phosphine borane compounds, the optically active ligands, the transition metal complexes, and the catalyzers, as well as the use of the catalyzers for organic transformation reactions. The present invention further relates to a method for producing phosphor compounds comprising imidazol groups and comprising optically active ligands, using phosphine borane compounds comprising imidazol groups.