A) cycloadditions
B) nucleophilic reactions
C) electrocyclic reactions
D) sigmatropic rearrangements
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A) cycloaddition reaction
B) electrophilic reaction
C) electrocyclic reaction
D) sigmatropic reaction
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A) The number of molecular orbitals formed is different from the number of atomic orbitals used.
B) The number of molecular orbitals formed is equal to the number of atomic orbitals used.
C) The number of molecular orbitals formed is equal to twice the number of atomic orbitals used.
D) The number of molecular orbitals formed is equal to half the number of atomic orbitals used.
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A) [2+2]
B) [4+2]
C) [4+4]
D) [0+2]
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A) Because the reaction is initiated by heat; the diene has four electrons and the dienophile has two electrons.
B) Because the reaction is initiated by light; the diene has four electrons and the dienophile has two electrons.
C) Because the reaction is initiated by heat; the dienophile has four electrons and the diene has two electrons.
D) Because the reaction is initiated by light; the dienophile has four electrons and the diene has two electrons.
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A) " orbitals are formed by the linear combination of two sp3 orbitals."
B) " orbitals are formed by the linear combination of two sp2 orbitals."
C) " orbitals are formed by the linear combination of two sp orbitals."
D) " orbitals are formed by the linear combination of two p orbitals."
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D
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A) The reactants contain one more bond than the product.
B) The product contains one more bond than the reactant.
C) A bond is broken in the reactant.
D) A bond is broken in the reactant.
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A) A sigmatropic reaction is an intramolecular pericyclic reaction.
B) In a sigmatropic reaction, bond is broken in one of the reactants.
C) The bonds rearrange in a sigmatropic reaction.
D) The number of bonds in the reactants and product differs in a sigmatropic reaction.
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A) Cycloaddition reactions can be initiated by heat only.
B) Cycloaddition reactions can be initiated by light only.
C) Cycloaddition reactions can be initiated by heat or light.
D) Cycloaddition reactions are identified by the number of electrons in the two products.
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A) electrocyclic reactions
B) acyclic reactions
C) cycloelimination reactions
D) electrophilic reactions
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A) I
B) II
C) III
D) IV
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B
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A) Only I
B) Only II
C) Only III
D) Only I and II
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B
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A) Thermal cycloadditions involving an even number of bonds proceed by a suprafacial pathway.
B) Thermal cycloadditions involving an odd number of bonds proceed by a suprafacial pathway.
C) Photochemical cycloadditions involving an odd number of bonds proceed by a suprafacial pathway.
D) Photochemical sycloadditions involving an even number of bonds proceed by an antarafacial pathway.
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A) [1,3]
B) [1,4]
C) [3,3]
D) [1,5]
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A) 3
B) 4
C) 5
D) 6
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A) Thermal cycloadditions involving an even number of bonds proceed by a suprafacial pathway.
B) Thermal cycloaddition involving an odd number of bonds proceed by an antarafacial pathway.
C) Photochemical cycloadditions involving an even number of bonds proceed by an antarafacial pathway.
D) Photochemical cycloadditions involving an even number of bonds proceed by a suprafacial pathway.
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A) A -bonding molecular orbital is formed when two p orbitals of similar phase overlap.
B) A -bonding molecular orbital is lower in energy than a -bonding molecular orbital.
C) A -bonding molecular orbital is formed when two p orbitals of opposite phase overlap.
D) Both the statements "a -bonding molecular orbital is formed when two p orbitals of similar phase overlap" and a -bonding molecular orbital is lower in energy than a -bonding molecular orbital" are true.
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A) cycloaddition reaction
B) electrocyclic reaction
C) electrophilic reaction
D) sigmatropic reaction
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A) cycloaddition reaction
B) electrophilic reaction
C) electrocyclic reaction
D) sigmatropic reaction
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A) The number of bonds in the conjugated polyene determines whether rotation is conrotatory or disrotatory.
B) Thermal electrocyclic reactions occur in a disrotatory fashion for a conjugated polyene with an odd number of bonds.
C) Thermal electrocyclic reactions occur in a conrotatory fashion for a conjugated polyene with an even number of bonds.
D) In thermal reactions, we consider the orbitals of the HOMO of the ground state electronic configuration to determine the course of the reaction.
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