A method for manufacturing isopulegol includes the step of diastereoselective ring-closing a citronellal using an aluminum compound of formula (1) below. In formula (1), X represents a halogen atom, Y represents a halogen atom or a hydrogen atom, and R.sub.1 represents a phenyl group or a cycloalkyl group of 5 to 12 carbons. ##STR00001##

A method for manufacturing isopulegol includes the step of diastereoselective ring-closing a citronellal using an aluminum compound of formula (1) below. In formula (1), X represents a halogen atom, Y represents a halogen atom or a hydrogen atom, and R.sub.1 represents a phenyl group or a cycloalkyl group of 5 to 12 carbons. ##STR00001##

A method for manufacturing isopulegol includes the step of diastereoselective ring-closing a citronellal using an aluminum compound of formula (1) below. In formula (1), X represents a halogen atom, Y represents a halogen atom or a hydrogen atom, and R.sub.1 represents a phenyl group or a cycloalkyl group of 5 to 12 carbons. ##STR00001##

A catalyst includes a carrier, and a metal obtained by reducing a metal ion supported on the carrier 1) in a supercritical state or 2) in a polar organic solvent, wherein the carrier is an inorganic porous body having a hierarchical porous structure. By employing the catalyst, it is possible to exhibit better catalytic activity than a conventional catalyst. Heat generation and spontaneous ignition are prevented because no organic porous body is used.

A catalyst includes a carrier, and a metal obtained by reducing a metal ion supported on the carrier 1) in a supercritical state or 2) in a polar organic solvent, wherein the carrier is an inorganic porous body having a hierarchical porous structure. By employing the catalyst, it is possible to exhibit better catalytic activity than a conventional catalyst. Heat generation and spontaneous ignition are prevented because no organic porous body is used.

A method for preparing dehydro-cyclofarnesal from dehydro-farnesal by cyclization in the presence of an acid may include the dehydro-farnesal being obtained from the farnesal by dehydrogenation and may further includes the cyclization being carried out in the presence of an acid selected from Lewis acids, Bronstedt acids, and zeolites. The synthesis of vitamin A using this method further includes the conversion of dehydro-cyclofarnesal into vitamin A.

A method for preparing dehydro-cyclofarnesal from dehydro-farnesal by cyclization in the presence of an acid may include the dehydro-farnesal being obtained from the farnesal by dehydrogenation and may further includes the cyclization being carried out in the presence of an acid selected from Lewis acids, Bronstedt acids, and zeolites. The synthesis of vitamin A using this method further includes the conversion of dehydro-cyclofarnesal into vitamin A.

The invention relates to monocarbonyl complexes of ruthenium and osmium with bi- and tridentate nitrogen and phosphine ligands. The invention relates to methods for preparing these complexes and the use of these complexes, isolated or prepared in situ, as catalysts for reduction reactions of ketones and aldehydes both via transfer hydrogenation or hydrogenation with hydrogen.

The invention relates to monocarbonyl complexes of ruthenium and osmium with bi- and tridentate nitrogen and phosphine ligands. The invention relates to methods for preparing these complexes and the use of these complexes, isolated or prepared in situ, as catalysts for reduction reactions of ketones and aldehydes both via transfer hydrogenation or hydrogenation with hydrogen.

The invention relates to monocarbonyl complexes of ruthenium and osmium with bi- and tridentate nitrogen and phosphine ligands. The invention relates to methods for preparing these complexes and the use of these complexes, isolated or prepared in situ, as catalysts for reduction reactions of ketones and aldehydes both via transfer hydrogenation or hydrogenation with hydrogen.