Organic Chemistry - Final
Exam with Complete Solutions (Rated
A+)
Name the 6 polar aprotic solvents-ANSWER-acetone, acetonitrile, DMSO, DMF, HMPA,
THF
Name the 5 polar protic solvents-ANSWER-acetic acid, ethanol, formic acid, methanol,
water
______ and ______ mechanisms are two step reactions that have _____
intermediates.-ANSWER-SN1; E1; 2 Intermediates each
______ and ______ mechanisms are one step reactions that have _____
intermediates.-ANSWER-SN2; E2; 1 Intermediate each
Allylic-ANSWER-resonance stabilized (carbon bonded directly to a C=C)
______ always proceeds with a backside attack, causing an inversion of configuration
at the stereogenic center. The _______ and _______ group are 180° from each other.-
ANSWER-SN2; Nucleophile; leaving group
During an SN2 reaction, what happens during the backside attack of a ring?-ANSWER-
Converts starting material with a cis group to being trans
What is the process to determining which product of a (beta) elimination reaction is the
major/minor?-ANSWER-First apply the Zaitsev rule (the major product has the more
substituted double bond); If a mixture of stereoisomers is possible, the major product is
the more stable stereoisomer.
Reaction Check List-ANSWER-SN1: ∧Nucl, ∨Base - 3°>, Protic (not 1°)
, SN2: ∧Nucl, ∨Base - 1°>, Aprotic, (not 3°)
E1: Bulky/Nonnucl. Base - 3°>, ∨Base, Protic, (not 1°)
E2: Bulky/Nonnucl. Base - 3°>, ∧Base, Aprotic, (not 1°)
When determining the more stable stereoisomer (to find the major product), what are 4
possible areas to look at?-ANSWER-1) If E2: Have to be anti-periplanar
2) If E1: Determine the more stable carbocation by higher R substitution
3) Alkene more stable when more R groups
4) Trans > Cis
Alkyne Synthesis is done with what type of reaction mechanism? How?-ANSWER-E2;
two successive dehydrohalogenation (E2) reactions
What ways can you gather enough information to rank substances by basicity?-
ANSWER-1) strongest acid → weakest (conj.) base 2) As pKa of H-A gets smaller, the
basicity of -A: increases 3) As Ka of H-A gets larger, the weaker the -A:
Definition of Lewis Acid-ANSWER-electron pair acceptor; any e- deficient species that is
capable of accepting an e- pair is a Lewis Acid; any molecule or ionic species that can
form new covalent bond by accepting an e- pair; all BL acids are Lewis acids, but
reverse is not necessarily true
Definition of Lewis Base-ANSWER-electron pair donor; structurally same as BL base
(both have e- pair); unlike BL base, Lewis can donate pair to anything electron deficient;
any molecule or ionic species that can form a new covalent bond by donating an e- pair.
Definition of B-L Acid. What requirements must they have? Give its symbol.-ANSWER-a
proton donor; must contain hydrogen; H-A
Definition of B-L Base. What requirements must they have? Give its symbol.-ANSWER-
A proton acceptor; must contain available e- pair (LP or π); B:
Exam with Complete Solutions (Rated
A+)
Name the 6 polar aprotic solvents-ANSWER-acetone, acetonitrile, DMSO, DMF, HMPA,
THF
Name the 5 polar protic solvents-ANSWER-acetic acid, ethanol, formic acid, methanol,
water
______ and ______ mechanisms are two step reactions that have _____
intermediates.-ANSWER-SN1; E1; 2 Intermediates each
______ and ______ mechanisms are one step reactions that have _____
intermediates.-ANSWER-SN2; E2; 1 Intermediate each
Allylic-ANSWER-resonance stabilized (carbon bonded directly to a C=C)
______ always proceeds with a backside attack, causing an inversion of configuration
at the stereogenic center. The _______ and _______ group are 180° from each other.-
ANSWER-SN2; Nucleophile; leaving group
During an SN2 reaction, what happens during the backside attack of a ring?-ANSWER-
Converts starting material with a cis group to being trans
What is the process to determining which product of a (beta) elimination reaction is the
major/minor?-ANSWER-First apply the Zaitsev rule (the major product has the more
substituted double bond); If a mixture of stereoisomers is possible, the major product is
the more stable stereoisomer.
Reaction Check List-ANSWER-SN1: ∧Nucl, ∨Base - 3°>, Protic (not 1°)
, SN2: ∧Nucl, ∨Base - 1°>, Aprotic, (not 3°)
E1: Bulky/Nonnucl. Base - 3°>, ∨Base, Protic, (not 1°)
E2: Bulky/Nonnucl. Base - 3°>, ∧Base, Aprotic, (not 1°)
When determining the more stable stereoisomer (to find the major product), what are 4
possible areas to look at?-ANSWER-1) If E2: Have to be anti-periplanar
2) If E1: Determine the more stable carbocation by higher R substitution
3) Alkene more stable when more R groups
4) Trans > Cis
Alkyne Synthesis is done with what type of reaction mechanism? How?-ANSWER-E2;
two successive dehydrohalogenation (E2) reactions
What ways can you gather enough information to rank substances by basicity?-
ANSWER-1) strongest acid → weakest (conj.) base 2) As pKa of H-A gets smaller, the
basicity of -A: increases 3) As Ka of H-A gets larger, the weaker the -A:
Definition of Lewis Acid-ANSWER-electron pair acceptor; any e- deficient species that is
capable of accepting an e- pair is a Lewis Acid; any molecule or ionic species that can
form new covalent bond by accepting an e- pair; all BL acids are Lewis acids, but
reverse is not necessarily true
Definition of Lewis Base-ANSWER-electron pair donor; structurally same as BL base
(both have e- pair); unlike BL base, Lewis can donate pair to anything electron deficient;
any molecule or ionic species that can form a new covalent bond by donating an e- pair.
Definition of B-L Acid. What requirements must they have? Give its symbol.-ANSWER-a
proton donor; must contain hydrogen; H-A
Definition of B-L Base. What requirements must they have? Give its symbol.-ANSWER-
A proton acceptor; must contain available e- pair (LP or π); B:
