Chem 3.2
What is the name of the steric interactions between an axial substituent and other axial hydrogens/substituents on the same face of the cyclohexane chair conformation?
1,3-diaxial repulsions
hat is the name of the steric interactions between an axial substituent and other axial hydrogens/substituents on the same face of the cyclohexane chair conformation?
1,3-diaxial repulsions
Select all the statements that correctly define the terms cis and trans in relation to cycloalkanes.
A cis isomer has two substituents on the same face of the ring. A trans isomer has one "up" substituent and one "down" substituent.
For a monosubstituted cyclohexane, the most stable conformation is one that places the substituent in the ______ position.
equatorial
Trans-1,4-dibromocylohexane is more stable than the cis isomer because only the trans isomer can adopt a conformation in which both bromine
equatorial
Select all of the possible orientations for the two substituents in a trans-1,2-disubstituted cyclohexane
Axial-axial Equatorial-equatorial
What are the two orientations of hydrogen atoms in a cyclohexane chair?
Axl, equatorial
Select all the chair conformations that represent trans-1,3-dibromocyclohexane (shown).
B C
The hydrogen atoms in the chair conformation of cyclohexane are divided into a set of six hydrogens and a set of six hydrogens.
Blank 1: axial Blank 2: equatorial
For a cycloalkane, two groups that are on the opposite side of the ring are described as transBlank 1Blank 1 trans , Correct Unavailable, whereas groups that are on the same side of the ring are described as cisBlank 2Blank 2 cis , Correct Unavailable.
Blank 1: trans Blank 2: cis
For any given cyclohexane molecule, there are possible chair conformations. A molecule moves between these conformations in a process known as ring
Blank 1: two or 2 Blank 2: inversion, interconversion, flipping, or flip
How does the IUPAC classify polycyclic ring systems?
By the number of bond disconnects required to make the system acyclic
Match each stereoisomer of a 1,4-disubstituted cyclohexane to its possible substituent orientations.
Choice, axial, equatorial axial, equatorial cis matches Choice, equatorial, axial equatorial, axial trans matches Choice, axial, axial axial, axial trans matches Choice, equatorial, equatorial equatorial, equatorial
Which of the following rings has four conformations with similar energy? Multiple choice question. Cyclohexane Cyclopropane Cycloheptane Cyclopentane
Cycloheptane
trans-1,4-dimethylcyclohexane
D B
Which structure shown is the most stable conformation of bromocyclohexane? Multiple choice question.
Structure A
Select all the statements that correctly describe the chair conformation of cyclohexane.
The bond angles are near 109.50. All hydrogen atoms on adjacent carbon atoms are staggered. Each carbon atom has one axial and one equatorial hydrogen atom.
True or false: Conformational analysis of cycloheptane and higher cycloalkanes is complicated due to an increase in the number of atoms, bonds, and possible conformations.
True
The most stable conformation for cyclohexane is the _____ conformation. In this conformation, _____ strain is eliminated because all internal bond angles are equal to 109.5°. All bonds to hydrogen atoms on adjacent carbon atoms are _____, and therefore torsional strain is minimized.
chair; angle; staggered
A heterocycle is a cyclic molecule in which at least one of the atoms of the ring is a
heteroatom
Structure A is _____ stable than structure B because one methyl has _____ strai
less; 1,3-diaxial
Structure A is _____ stable than structure B because one methyl has _____ strain.
less; 1,3-diaxial
What is the name of the following spiro compound?
spiropentane 2.2
True or false: A cyclohexane ring can adopt two different chair conformations.
true
