Oppolzer Sultam
A rigid chiral auxiliary derived from camphor used to control facial selectivity.
Context: Useful for Diels–Alder and alkylation reactions with high selectivity.
Example: Sultam-controlled cycloadditions.
Related Terms: Chiral Auxiliary, Asymmetric Synthesis.
Reference: Oppolzer, Tetrahedron (1987).
Optical Activity
Rotation of plane-polarized light by chiral substances.
Context: Classical signature of chirality; still used for QC when specific rotation is compendial.
Example: [α]D^20 measurements for amino acids.
Related Terms: Polarimetry, Specific Rotation.
Reference: Atkins, Physical Chemistry.
Optical Activity
Definition: The ability of chiral substances to rotate the plane of polarized light.
Context: Classical indicator of chirality; measured via polarimetry to assess enantiomeric purity.
Example: (+)-Lactic acid rotates plane-polarized light to the right.
Related Terms: Optical Rotation; Specific Rotation; Polarimetry.
Reference: Atkins, P. W. Physical Chemistry. Oxford University Press, 2010.
Optical Purity
Measured enantiomeric purity derived from specific rotation relative to a pure enantiomer.
Context: Historical measure that correlates with ee when linear.
Example: Optical purity ≈ ee for simple systems.
Related Terms: Enantiomeric Excess, Polarimetry.
Reference: Morrison & Boyd.
Optical Rotation
Definition: The observed angle by which plane-polarized light is rotated upon passing through a chiral sample.
Context: Dependent on path length, concentration, wavelength, and temperature; denoted [?]?²?.
Example: [?]?²? = +12.5° (c 1.0, MeOH).
Related Terms: Optical Activity; Specific Rotation; Polarimetry.
Reference: USP-NF General Chapter <781> Optical Rotation.
Optical Rotatory Dispersion (ORD)
Wavelength dependence of optical rotation.
Context: Precursor to CD; used for stereochemical assignment and conformational analysis.
Example: ORD curves distinguishing sugar stereoisomers.
Related Terms: Circular Dichroism, Cotton Effect.
Reference: Lightner & Gurst, Organic Conformational Analysis (1980).
Organocatalysis
Enantioselective catalysis with small organic molecules.
Context: Metal-free, green, and scalable approaches for key stereogenic steps.
Example: Proline-catalyzed aldol reactions.
Related Terms: Iminium Catalysis, Enamine Catalysis.
Reference: List & Barbas, JACS (2000).