Biomaterial Database

[Asymmetric synthesis of multi-substituted β-lactams via C-N axially chiral enolates in intramolecular conjugate addition]. 2012

Tomoyuki Yoshimura

Institute for Chemical Research, Kyoto University, Kyoto, Japan. tyoshimu@fos.kuicr.kyoto-u.ac.jp

The synthesis of β-lactams with contiguous tetra- and trisubstituted carbon centers has been accomplished via the 4-exo-trig intramolecular conjugate addition of C-N axially chiral enolates generated from α-amino acid derivatives. Use of a metal carbonate in a protic solvent (i.e., Cs(2)CO(3) in EtOH) was found to be critical for the success of the reaction. Under optimized reaction conditions, axially chiral enolates were generated in very low concentration, thereby favoring intramolecular conjugate addition while minimizing intermolecular side reactions. The highly strained β-lactam enolates formed through this reversible intramolecular conjugate addition were rapidly protonated by EtOH in the reaction media to afford β-lactams in up to 97% ee.

UI	MeSH Term	Description	Entries
D008968	Molecular Conformation	The characteristic three-dimensional shape of a molecule.	Molecular Configuration,3D Molecular Structure,Configuration, Molecular,Molecular Structure, Three Dimensional,Three Dimensional Molecular Structure,3D Molecular Structures,Configurations, Molecular,Conformation, Molecular,Conformations, Molecular,Molecular Configurations,Molecular Conformations,Molecular Structure, 3D,Molecular Structures, 3D,Structure, 3D Molecular,Structures, 3D Molecular
D002254	Carbonates	Salts or ions of the theoretical carbonic acid, containing the radical CO2(3-). Carbonates are readily decomposed by acids. The carbonates of the alkali metals are water-soluble; all others are insoluble. (From Grant & Hackh's Chemical Dictionary, 5th ed)	Carbonate
D002586	Cesium	A member of the alkali metals. It has an atomic symbol Cs, atomic number 55, and atomic weight 132.91. Cesium has many industrial applications, including the construction of atomic clocks based on its atomic vibrational frequency.	Caesium,Caesium-133,Cesium-133,Caesium 133,Cesium 133
D000431	Ethanol	A clear, colorless liquid rapidly absorbed from the gastrointestinal tract and distributed throughout the body. It has bactericidal activity and is used often as a topical disinfectant. It is widely used as a solvent and preservative in pharmaceutical preparations as well as serving as the primary ingredient in ALCOHOLIC BEVERAGES.	Alcohol, Ethyl,Absolute Alcohol,Grain Alcohol,Alcohol, Absolute,Alcohol, Grain,Ethyl Alcohol
D000596	Amino Acids	Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.	Amino Acid,Acid, Amino,Acids, Amino
D012997	Solvents	Liquids that dissolve other substances (solutes), generally solids, without any change in chemical composition, as, water containing sugar. (Grant & Hackh's Chemical Dictionary, 5th ed)	Solvent
D013237	Stereoisomerism	The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)	Molecular Stereochemistry,Stereoisomers,Stereochemistry, Molecular,Stereoisomer
D047090	beta-Lactams	Four-membered cyclic AMIDES, best known for the PENICILLINS based on a bicyclo-thiazolidine, as well as the CEPHALOSPORINS based on a bicyclo-thiazine, and including monocyclic MONOBACTAMS. The BETA-LACTAMASES hydrolyze the beta lactam ring, accounting for BETA-LACTAM RESISTANCE of infective bacteria.	beta-Lactam,4-Thia-1-Azabicyclo(3.2.0)Heptanes,4-Thia-1-Azabicyclo(4.2.0)Octanes,beta Lactam,beta Lactams
D055601	Organic Chemistry Phenomena	The conformation, properties, reaction processes, and the properties of the reactions of organic carbon compounds.	Organic Chemistry Concepts,Organic Chemistry Processes,Organic Chemistry Phenomenon,Organic Chemistry Process,Chemistry Process, Organic,Chemistry Processes, Organic,Concept, Organic Chemistry,Concepts, Organic Chemistry,Organic Chemistry Concept,Phenomena, Organic Chemistry,Phenomenon, Organic Chemistry,Process, Organic Chemistry,Processes, Organic Chemistry
D019943	Amino Acid Substitution	The naturally occurring or experimentally induced replacement of one or more AMINO ACIDS in a protein with another. If a functionally equivalent amino acid is substituted, the protein may retain wild-type activity. Substitution may also diminish, enhance, or eliminate protein function. Experimentally induced substitution is often used to study enzyme activities and binding site properties.	Amino Acid Substitutions,Substitution, Amino Acid,Substitutions, Amino Acid