Page 34 Flashcards
What does the transition state of an E2 reaction consist of?
A: Four atoms: one hydrogen atom, two carbon atoms, and the leaving group (X) aligned in a plane
What are the two possible geometries for the C-H and C-X bonds to be coplanar in E2 reactions?
A: Syn periplanar and anti periplanar.
What does “syn periplanar” mean in E2 reactions?
A: The hydrogen and leaving group (X) are on the same side of the molecule.
What does “anti periplanar” mean in E2 reactions?
A: The hydrogen and leaving group (X) are on opposite sides of the molecule.
Which geometry, syn periplanar or anti periplanar, is preferred in E2 reactions?
A: Anti periplanar geometry is generally preferred due to lower steric hindrance and better orbital overlap.
Why is anti periplanar geometry often favored in E2 reactions?
A: It minimizes steric interactions and maximizes overlap between the breaking C-H and C-X bonds.
What role does the orientation of the leaving group and β hydrogen play in E2 stereochemistry?
A: Their coplanar alignment ensures proper overlap of orbitals for elimination to occur.
What happens if the C-H and C-X bonds are not coplanar in an E2 reaction?
A: Elimination cannot proceed efficiently due to improper orbital overlap.
Does the stereochemistry of the starting material influence the stereochemical outcome of E2 reactions?
A: Yes, the spatial arrangement of atoms affects which alkene product forms.
In an E2 reaction, what happens to the molecule’s geometry as the reaction proceeds?
A: The molecule transitions from a planar arrangement in the transition state to a final alkene product with defined stereochemistry.
