cyclization

Forming molecular rings

Cyclization is the chemical process of forming a ring structure from an open-chain compound.

The atoms at each end of a molecular chain bond together, closing the loop: The reaction proceeds through cyclization to form a six-membered ring.

The term appears throughout organic chemistry and biochemistry, where ring formation is fundamental to synthesizing drugs, natural products, and biological molecules.

mechanism

intramolecular

Within a single molecule

intermediateBetween two levels
activationSetting into operation
barrierObstruction preventing passage

energy · kinetics · thermodynamics · pathway · selectivity · concerted · stepwise · radical · cationic · anionic

organic

nucleophile

Electron-pair donating species

electrophileElectron-pair acceptor species
alkeneDoubly-bonded carbon compound
alkyneTriple-bonded carbon compound

conjugation · aromaticity · lactone · Diels-Alder · Friedel-Crafts · Bergman · diene

ring

fused

Joined by melting together

bridgedConnected across a gap
tricyclicTriple-ring chemical structure
heterocyclicRing with non-carbon members

aromatic · saturated · unsaturated · annulus · cyclopropane · cyclopentane · cyclohexane

biochemical

enzyme

Protein that hastens reactions

biosynthesisLiving production of molecules
terpeneIsoprene-based plant compound
alkaloidNitrogenous plant compound

peptide · steroid · squalene · ATP · cofactor · substrate · folding · disulfide · DNA · RNA

Opposites

molecular structure formation

cyclizationring-opening

Cleaving a cyclic structure

linearization · polymerization · fragmentation · bond cleavage

molecular topology

cyclizationacyclic

Lacking repeated patterns

linear

Family

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