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SEGPHOS
SEGPHOS is a chiral ligand developed by Takasago that is used in asymmetric synthesis. It was developed after BINAP BINAP (2,2′-bis(diphenylphosphino)-1,1′-binaphthyl) is an organophosphorus compound. This chiral diphosphine ligand is widely used in asymmetric synthesis. It consists of a pair of 2-diphenylphosphinonaphthyl groups linked at the 1 and 1 ... and was investigated since it has a narrower dihedral angle between the aromatic faces. This was predicted and then confirmed to increase the enantioselectivity and activity of metal complexes of SEGPHOS. After its commercialization, SEGPHOS and its substituted derivatives have been found to constitute a privileged ligand class for a variety of transition metal catalysts and chemical transformations beyond its original application in ruthenium-catalyzed enantioselective hydrogenation. In addition to the parent ligand bearing phenyl groups on the phosphorus atoms, the bulkier derivatives DM-SEGPHOS and DTBM-SEGPHOS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Segphos Family
SEGPHOS is a chiral ligand developed by Takasago that is used in asymmetric synthesis. It was developed after BINAP BINAP (2,2′-bis(diphenylphosphino)-1,1′-binaphthyl) is an organophosphorus compound. This chiral diphosphine ligand is widely used in asymmetric synthesis. It consists of a pair of 2-diphenylphosphinonaphthyl groups linked at the 1 and 1 ... and was investigated since it has a narrower dihedral angle between the aromatic faces. This was predicted and then confirmed to increase the enantioselectivity and activity of metal complexes of SEGPHOS. After its commercialization, SEGPHOS and its substituted derivatives have been found to constitute a privileged ligand class for a variety of transition metal catalysts and chemical transformations beyond its original application in ruthenium-catalyzed enantioselective hydrogenation. In addition to the parent ligand bearing phenyl groups on the phosphorus atoms, the bulkier derivatives DM-SEGPHOS and DTBM-SEGPHOS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BINAP
BINAP (2,2′-bis(diphenylphosphino)-1,1′-binaphthyl) is an organophosphorus compound. This chiral diphosphine ligand is widely used in asymmetric synthesis. It consists of a pair of 2-diphenylphosphinonaphthyl groups linked at the 1 and 1′ positions. This C2-symmetric framework lacks a stereogenic atom, but has axial chirality due to restricted rotation ( atropisomerism). The barrier to racemization is high due to steric hindrance, which limits rotation about the bond linking the naphthyl rings. The dihedral angle between the naphthyl groups is approximately 90°. The natural bite angle is 93°. Use as ligand in asymmetric catalysis BINAP is used in organic synthesis for enantioselective transformations catalyzed by its complexes of ruthenium, rhodium, and palladium. As pioneered by Ryōji Noyori and his co-workers, rhodium complexes of BINAP are useful for the synthesis of (–)-menthol. Silver complexes are also important; BINAP- AgF can be used to enantioselect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chirality (chemistry)
In chemistry, a molecule or ion is called chiral () if it cannot be superposed on its mirror image by any combination of rotation (geometry), rotations, translation (geometry), translations, and some Conformational isomerism, conformational changes. This geometric property is called chirality (). The terms are derived from Ancient Greek χείρ (''cheir'') 'hand'; which is the canonical example of an object with this property. A chiral molecule or ion exists in two stereoisomers that are mirror images of each other, called enantiomers; they are often distinguished as either "right-handed" or "left-handed" by their absolute configuration or some other criterion. The two enantiomers have the same chemical properties, except when reacting with other chiral compounds. They also have the same physics, physical properties, except that they often have opposite optical activity, optical activities. A homogeneous mixture of the two enantiomers in equal parts is said to be racemic mixtu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ligand
In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electron pairs, often through Lewis bases. The nature of metal–ligand bonding can range from covalent to ionic. Furthermore, the metal–ligand bond order can range from one to three. Ligands are viewed as Lewis bases, although rare cases are known to involve Lewis acidic "ligands". Metals and metalloids are bound to ligands in almost all circumstances, although gaseous "naked" metal ions can be generated in a high vacuum. Ligands in a complex dictate the reactivity of the central atom, including ligand substitution rates, the reactivity of the ligands themselves, and redox. Ligand selection requires critical consideration in many practical areas, including bioinorganic and medicinal chemistry, homogeneous catalysis, and environmental chemi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Takasago International Corporation
is a major international producer of flavours and fragrances headquartered in Japan, with presence in 27 countries and regions worldwide. Takasago ranked 8th overall and 1st in Asia on the Global Top Food Flavours and Fragrances Companies list published by FoodTalks in 2021. History Takasago International Corporation was founded on 9 February 1920 as the Takasago Perfumery Company Limited. In 1938, the headquarters of Takasago was moved to Taihoku (modern-day Taipei), and in 1940, a branch office and factory were set up in Shanghai. In 1945, the Taipei headquarters and Shanghai office were taken over by Republic of China. In 1951, the Takasago Chemical Company in Taipei was closed and a new company, Takasago Chemical Industry Company was founded. The new company later changed its name to Takasago Perfumery Industry Company and merged with Takasago Perfumery Company. During the 1960s, Takasago established offices in New York City and Paris, and their headquarters were moved to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asymmetric Synthesis
Enantioselective synthesis, also called asymmetric synthesis, is a form of chemical synthesis. It is defined by IUPAC as "a chemical reaction (or reaction sequence) in which one or more new elements of chirality are formed in a substrate molecule and which produces the stereoisomeric (enantiomeric or diastereomeric) products in unequal amounts." Put more simply: it is the synthesis of a compound by a method that favors the formation of a specific enantiomer or diastereomer. Enantiomers are stereoisomers that have opposite configurations at every chiral center. Diastereomers are stereoisomers that differ at one or more chiral centers. Enantioselective synthesis is a key process in modern chemistry and is particularly important in the field of pharmaceuticals, as the different enantiomers or diastereomers of a molecule often have different biological activity. Overview Many of the building blocks of biological systems such as sugars and amino acids are produced exclusively as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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