Interpretation:
Only the 2E,4E isomer is obtained in practice by opening of trans-3,4-Dimethylcyclobutene by two conrotatory paths to give symmetry-allowed products either (2E,4E)-2,4-hexadiene or (2Z,4Z)-2,4-hexadiene.
Concept introduction:
An electrocyclic ring-opening reaction is a reaction in which a σ bond of a cyclic reactant is cleaved to form a conjugated product with one more π bond. It occurs only when like phases of orbitals can overlap to form a bond. Such a reaction is symmetry allowed. It cannot occur between orbitals of opposite phase. Such a reaction is symmetry forbidden. To form a bond, the p orbitals on the terminal carbons must rotate so that like phases can interact to form the new sigma bond. Two modes of rotation are possible - When like phases of the p orbitals are on the same side of the molecule, the two orbitals must rotate in opposite direction one clockwise and one counterclockwise. Rotation in opposite directions is said to be disrotatory.
When like phases of the p orbitals are on opposite sides of the molecule, the two orbitals must rotate in the same direction both clockwise or both counterclockwise. Rotation in the same direction is said to be conrotatory.
Trending nowThis is a popular solution!
Chapter 30 Solutions
Bundle: Organic Chemistry, 9th, Loose-Leaf + OWLv2, 4 terms (24 months) Printed Access Card
- The number of imaginary replicas of a system of N particlesA) can never become infiniteB) can become infiniteC) cannot be greater than Avogadro's numberD) is always greater than Avogadro's number.arrow_forwardElectronic contribution to the heat capacity at constant volume A) is always zero B) is zero, except for excited levels whose energy is comparable to KT C) equals 3/2 Nk D) equals Nk exp(BE)arrow_forwardPlease correct answer and don't used hand raitingarrow_forward
- Calculate the packing factor of CaTiO3. It has a perovskite structure. Data: ionic radii Co²+ = 0.106 nm, Ti4+ = 0.064 nm, O² = 0.132 nm; lattice constant is a = 2(rTi4+ + ro2-). Ca2+ 02- T14+ Consider the ions as rigid spheres. 1. 0.581 or 58.1% 2. -0.581 or -58.1 % 3. 0.254 or 25.4%arrow_forwardGeneral formula etherarrow_forwardPlease provide the retrosynthetic analysis and forward synthesis of the molecule on the left from the starting material on the right. Please include hand-drawn structures! will upvote! Please correct answer and don't used hand raitingarrow_forward
- Please provide the retrosynthetic analysis and forward synthesis of the molecule on the left from the starting material on the right. Please include hand-drawn structures! will upvote!arrow_forward(please correct answer and don't used hand raiting) Please provide the retrosynthetic analysis and forward synthesis of the molecule on the left from the starting material on the right. Please include hand-drawn structures! will upvote!arrow_forwardCaTiO3 has a perovskite structure. Calculate the packing factor.Data: ionic radii Co+2 = 0.106 nm, Ti+4 = 0.064 nm, O-2 = 0.132 nm; lattice constant is a = 2(rTi4+ + rO-2).(a) 0.581(b) -0.581(c) 0.254(d) -0.254arrow_forward
- In the initial linear section of the stress-strain curve of a metal or alloy. Explain from the point of view of atomic structure?(a) No, the atomic level properties of the material can never be related to the linear section.(b) The elastic zone is influenced by the strength of the bonds between atoms.(c) The stronger the bond, the less rigid and the lower the Young's Modulus of the material tested.(d) The stronger the bond, the less stress is necessary to apply to the material to deform it elastically.arrow_forwardThe degree of polymerization of polytetrafluoroethylene (Teflon) is 7500 (mers/mol). If all polymer chains have equal length, state the molecular weight of the polymer and the total number of chains in 1000 g of the polymer(a) 50 000 g/mol; 0.03·1020 chains(b) 100 000 g/mol; 1.03·1020 chains(c) 750 000 g/mol; 8.03·1020 chainsarrow_forwardIn natural rubber or polyisoprene, the trans isomer leads to a higher degree of crystallinity and density than the cis isomer of the same polymer, because(a) it is more symmetrical and regular.(b) it is less symmetrical.(c) it is irregular.arrow_forward
Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning