Ch04_Cycloalkanes_and_their_stereochemistry

Cycloalkanes

Saturated cyclic hydrocarbons with the general formula CnH2n.

Cis-Trans Isomerism

A form of stereoisomerism where substituents are on the same side (cis) or opposite sides (trans) of a ring.

Angle Strain

Strain in a cycloalkane due to bond angles deviating from the ideal tetrahedral value of 109 degrees.

Torsional Strain

Strain caused by eclipsing interactions between neighboring bonds in a cycloalkane.

Steric Strain

Strain resulting from repulsive interactions between non-bonded atoms that are too close together.

Chair Conformation

A strain-free three-dimensional shape adopted by cyclohexane, with bond angles near 109 degrees.

Axial Position (cyclohexane)

A substituent position on the cyclohexane ring that is parallel to the ring axis.

Equatorial Position (cyclohexane)

A substituent position on the cyclohexane ring that is in the rough plane of the ring.

Ring-Flip (cyclohexane)

The process by which a chair cyclohexane conformation interconverts between its axial and equatorial substituent positions.

1,3-Diaxial Interaction

Steric strain that arises when an axial substituent interacts with hydrogens on carbons three away in a cyclohexane structure.

Stereochemical Isomers

Compounds that differ in the spatial arrangement of atoms while having the same molecular formula.

Polyclyclic Molecule

A molecule that contains two or more interconnected rings.

Conformational Analysis

The study of the three-dimensional shapes (conformations) of molecules.

Cyclopropane

A three-membered ring compound characterized by significant angle strain due to its small ring size, resulting in higher reactivity compared to larger rings.

Cyclobutane

A four-membered ring compound that has less angle strain than cyclopropane but more torsional strain.

Cyclopentane

A five-membered ring with negligible angle strain that adopts a puckered conformation to minimize torsional strain.

Strain Energy

The extra energy present in a molecule due to various types of strain (angle, torsional, and steric) compared to a strain-free reference.

Alicyclic Compounds

Compounds that are cyclic but are not aromatic; they contain carbon atoms arranged in a ring and can be saturated or unsaturated.

Boat Conformation

A less stable conformation of cyclohexane that has the shape of a boat, characterized by two axial hydrogens on each end and steric interactions between these hydrogens.

Bridgehead Atom

An atom located at the intersection of two or more rings in a polycyclic compound.

Twist Boat Conformation

A conformation of cyclohexane that reduces steric strain by twisting the boat shape, resulting in less torsional strain compared to the regular boat conformation.