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1 | |
The primary reason for the stability of allylic cations is? |
| | A) | inductive stabilization by electron withdrawing groups. |
| | B) | inductive stabilization by electron donating groups. |
| | C) | resonance stabilization by an unoccupied adjacent p bond. |
| | D) | resonance stabilization by an occupied adjacent p bond. |
| | E) | donation of a lone pair of electrons from another atom. |
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2 | |
1,4-cyclohexadiene contains __ vinylic and __ allylic hydrogen atoms?
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| | A) | 2 and 2 respectively. |
| | B) | 3 and 3 respectively. |
| | C) | 4 and 4 respectively. |
| | D) | 2 and 4 respectively. |
| | E) | 4 and 2 respectively. |
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3 | |
NBS (N-bromosuccinimide) is? |
| | A) | used for adding a bromide atom to an alkene. |
| | B) | used for adding a succinimide group to an alkene. |
| | C) | used as a solvent. |
| | D) | used to add a bromine atom at the allylic carbon. |
| | E) | used to hydrogenate allylic systems. |
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4 | |
Conjugated alkenes are characterized by? |
| | A) | alternating p and s bonds. |
| | B) | adjacent p bonds. |
| | C) | p bonds separated by two or more s bonds. |
| | D) | a cyclic system containing 6 p electrons. |
| | E) | adjacent sp hybridized carbon atoms. |
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5 | |
The relative order of stability for isomeric dienes is? |
| | A) | isolated > cumulated > conjugated |
| | B) | isolated > conjugated > cumulated |
| | C) | conjugated > isolated > cumulated |
| | D) | conjugated > cumulated > isolated |
| | E) | cumulated > conjugated > isolated |
| | F) | cumulated > isolated > conjugated |
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6 | |
The conformation of the following diene is?
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| | A) | s-cis. |
| | B) | s-trans. |
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7 | |
Can allenes be chiral? |
| | A) | Yes. |
| | B) | No. |
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8 | |
Kinetic control refers to? |
| | A) | the rate of a reaction. |
| | B) | the product distribution being controlled by the rates of competing reactions. |
| | C) | the product distribution being controlled by the relative stability of products. |
| | D) | the use of heat to speed a reaction. |
| | E) | the use of catalysts to speed the reaction. |
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9 | |
1,4 additions are? |
| | A) | additions of 1 or 4 atoms to the diene. |
| | B) | the addition of a reagent to atoms 1 and 4 of the alkene. |
| | C) | the addition of reagents to atoms 1 and 4 of a cumulated diene. |
| | D) | the addition of a reagent to atoms 1 and 4 of the conjugated diene. |
| | E) | the addition of a reagent to atoms 1 and 4 of the isolated diene. |
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10 | |
A Diels-Alder reaction is? |
| | A) | the addition of two alkenes producing a cycloalkane. |
| | B) | the addition of two alkenes producing a cycloalkene. |
| | C) | the addition of an alkene and a diene producing a cycloalkene. |
| | D) | the addition of an alkene and a diene producing a cycloalkane. |
| | E) | the addition of an alkene and a diene producing a cyclodiene. |
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11 | |
A good dieneophile for a Diels-Alder reaction is? |
| | A) | an alkene. |
| | B) | an alkyne. |
| | C) | an alkene with an electron donating group attached to it. |
| | D) | an alkyne with an electron donating group attached to it. |
| | E) | an alkene with an electron withdrawing group attached to it. |
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12 | |
The orbitals which react in a Diels-Alder reaction are? |
| | A) | the HOMO of the diene and LUMO of the dieneophile. |
| | B) | the LUMO of the diene and HOMO of the dieneophile. |
| | C) | the HOMO of the diene and LUMO+1 of the dieneophile. |
| | D) | the HOMO-1 of the diene and LUMO of the dieneophile. |
| | E) | the HOMO-1 of the diene and LUMO+1 of the dieneophile. |
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