Z-(Zusammen)
Definition: A geometric descriptor indicating that the higher-priority substituents on a double bond are on the same side.
Context: Used to differentiate stereoisomeric alkenes and similar compounds; "Z" is the counterpart to "E".
Example: Z-2-butene has both methyl groups on the same side of the C=C bond.
Related Terms: E-; Geometric Isomerism; CIP Rules.
Reference: Cahn, Ingold & Prelog (1966).
Zig-Zag Representation
Definition: A skeletal line drawing convention where carbon-carbon bonds are drawn in a zig-zag pattern, implicitly showing sp3 geometry.
Context: Simplifies organic structure representation and emphasizes chain conformation.
Example: n-Hexane drawn as a zig-zag carbon backbone.
Related Terms: Fischer Projection; Newman Projection; Sawhorse Projection.
Reference: Clayden et al., Organic Chemistry (2012).
Zimmerman–Traxler Model
Definition: Chair-like transition state model for aldol reactions linking geometry to syn/anti outcome.
Context: Guides stereochemical planning in polyketide synthesis.
Example: Evans oxazolidinone-controlled aldol.
Related Terms: Aldol Reaction, Chiral Auxiliary.
Reference: Zimmerman & Traxler, JACS (1957).