Question 1

Provide the major organic product for the reaction sequence:

Accepted Answer

This is an example of the Williamson ether synthesis. The first step deprotonates the alcohol to form an alkoxide. The second step is simply an S_N2 substitution.

Question 2

Complete the reaction:

Accepted Answer

Under basic or neutral conditions, a nucleophile will add to the less substituted epoxide carbon.

Question 3

Propose a multistep synthesis for the epoxide (which will be prepared as the racemate) from 1-butyne, benzyl bromide, and any other reagents. As usual, show the reagents and the major organic product for each step.

Accepted Answer

There are many variations on the synthesis (see notes below the synthesis).
   At (*) several variations are possible. For example, one could let benzyl bromide react with the conjugate base of acetylene, and then elaborate that into the alcohol via hydrogenation with a poisoned catalyst and hydroboration/oxidation. Or one could treat the alkene with HBr/peroxides.

Question 4

Complete the reaction by giving the major organic product:

Accepted Answer

A Grignard reagent w

Question 5

Complete the reaction:

Accepted Answer

Oxonium salts react

Question 6

Compound A (C5H11BrO), when dissolved in ethanol containing one equivalent of NaOH, forms a product B. Identify compound A and give a two-step curved-arrow mechanism for its conversion into B. In each step of the curved-arrow mechanism identify the Brønsted acids (BA), Brønsted bases (BB), nucleophiles (N), electrophiles (E), and leaving groups (LG).

Accepted Answer

The starting material has no unsaturatio

Question 7

Complete the reaction by giving the major organic product. The product formed is a racemate-give the stereochemistry of either enantiomer.

Accepted Answer

This is a ring-opening reaction under ac

Question 8

Using curved-arrow notation, propose a mechanism for the transformation that takes into account the stereochemistry of the product. (Hint: Note that two inversions of stereochemistry = one retention.)

Accepted Answer

The hint should have called your attenti

Question 9

The reaction fails to generate the indicated ether. Explain why and what product is generated instead.

Accepted Answer

The alkoxide will be generated

Question 10

Outline a synthesis to give the transformation:

Accepted Answer

This transformation can be achieved in s

Question 11

Give the structure of the nucleophile that would react with benzyl chloride (PhCH2Cl) to give the sulfonium salt:

Accepted Answer

The nucleo

Question 12

cis-3-Hexene is treated with OsO4 (osmium tetroxide), then water. Which one statement is true about the product?

Accepted Answer

A)  The product is the meso stereoisomer of 3,4-hexanediol, and it is optically inactive. 
B)  The product is mostly the (3S,4R) stereoisomer of 3,4-hexanediol, and it is optically active. 
C)  The product is mostly optically active (3S,4S)-3,4-hexanediol. 
D)  The product is mostly optically active (3R,4R)-3,4-hexanediol. 
E)  The product is a racemate consisting of equal amounts of (3S,4S)-3,4-hexanediol and (3R,4R)-3,4-hexanediol.f. 
None of the these is correct because 3,4-hexanediol is not the product of this reaction. 
A)  The product is the meso stereoisomer of 3,4-hexanediol, and it is optically inactive. 
B)  The product is mostly the (3S,4R) stereoisomer of 3,4-hexanediol, and it is optically active. 
C)  The product is mostly optically active (3S,4S)-3,4-hexanediol. 
D)  The product is mostly optically active (3R,4R)-3,4-hexanediol. 
E)  The product is a racemate consisting of equal amounts of (3S,4S)-3,4-hexanediol and (3R,4R)-3,4-hexanediol.f. 
None of the these is correct because 3,4-hexanediol is not the product of this reaction.

Question 13

Select the one true statement about biological reactions involving S-adenosylmethionine (SAM).

Accepted Answer

A)  The sulfur acts as a nucleophile. 
B)  The sulfur acts as a nucleophile in scavenging unwanted epoxides. 
C)  The sulfur (with its two attached groups) acts as a leaving group. 
D)  The R1 and R2 groups attached to the sulfur act as electrophiles. 
E)  The methyl group attached to sulfur acts as a nucleophile. 
A)  The sulfur acts as a nucleophile. 
B)  The sulfur acts as a nucleophile in scavenging unwanted epoxides. 
C)  The sulfur (with its two attached groups) acts as a leaving group. 
D)  The R1 and R2 groups attached to the sulfur act as electrophiles. 
E)  The methyl group attached to sulfur acts as a nucleophile.

Question 14

Complete the missing starting material. Be sure to clearly show stereochemistry.

Accepted Answer

Epoxides are generated from th

Question 15

Propose a synthetic scheme to carry out the transformation. Show the product of each step.

Accepted Answer

Two routes are shown to form the alkyl h

Question 16

Draw the missing organic product.

Accepted Answer

Direct oxidation of a sulfide

Question 17

In the SN2 reaction, sulfur is the "leaving atom" in the leaving group. The products are a single sulfide (R-S-R´) and a single ether.
   a. Draw the structures of the products in the appropriate boxes.
b. On the reaction, draw the curved-arrow notation for this reaction.

Accepted Answer

Attack of the nucleo

Question 18

Provide the missing product and the curved-arrow notation for this reaction.

Accepted Answer

The mechanism is as follows. W

Question 19

Complete the reaction sequence by providing the structures of the missing compounds.

Accepted Answer

The first reaction deprotonate

Question 20

Provide the missing product. Clearly show stereochemistry of the product.

Accepted Answer

An alkene reacts with mCPBA to

Exam 12: The Chemistry of Ethers, Epoxides, Glycols, and Sulfides

Provide the major organic product for the reaction sequence:

Complete the reaction:

Propose a multistep synthesis for the epoxide (which will be prepared as the racemate) from 1-butyne, benzyl bromide, and any other reagents. As usual, show the reagents and the major organic product for each step.

Complete the reaction by giving the major organic product:

Complete the reaction:

Complete the reaction by giving the major organic product. The product formed is a racemate-give the stereochemistry of either enantiomer.

Using curved-arrow notation, propose a mechanism for the transformation that takes into account the stereochemistry of the product. (Hint: Note that two inversions of stereochemistry = one retention.)

The reaction fails to generate the indicated ether. Explain why and what product is generated instead.

Outline a synthesis to give the transformation:

Give the structure of the nucleophile that would react with benzyl chloride (PhCH2Cl) to give the sulfonium salt:

cis-3-Hexene is treated with OsO4 (osmium tetroxide), then water. Which one statement is true about the product?

Select the one true statement about biological reactions involving S-adenosylmethionine (SAM).

Complete the missing starting material. Be sure to clearly show stereochemistry.

Propose a synthetic scheme to carry out the transformation. Show the product of each step.

Draw the missing organic product.

In the SN2 reaction, sulfur is the "leaving atom" in the leaving group. The products are a single sulfide (R-S-R´) and a single ether. a. Draw the structures of the products in the appropriate boxes. b. On the reaction, draw the curved-arrow notation for this reaction.

Provide the missing product and the curved-arrow notation for this reaction.

Complete the reaction sequence by providing the structures of the missing compounds.

Provide the missing product. Clearly show stereochemistry of the product.

Chemical Bonding and Chemical Structure

Alkanes and Organic Nomenclature

The Curved-Arrow Notation, Resonance, Acids and Bases, and Chemical Equilibrium

Introduction to Alkenes and Alkynes

Addition Reactions of Alkenes and Alkynes

Principles of Stereochemistry

Cyclic Compounds and Reaction Stereochemistry

Nomenclature and Noncovalent Intermolecular Interactions

The Chemistry of Alkyl Halides

Free-Radical Reactions, Main-Group Organometallic Compounds, and Carbenes

The Chemistry of Alcohols and Thiols

Introduction to Spectroscopy

Nuclear Magnetic Resonance Spectroscopy

Dienes and Aromaticity

The Chemistry of Benzene and Its Derivatives

Allylic and Benzylic Reactivity

The Chemistry of Aryl Halides, Vinylic Halides, and Phenols

The Chemistry of Aldehydes and Ketones

The Chemistry of Carboxylic Acids

The Chemistry of Carboxylic Acid Derivatives

The Chemistry of Enolate Ions, Enols, and Α,β-Unsaturated Carbonyl Compounds

The Chemistry of Amines

Carbohydrates

The Chemistry of Thioesters, Phosphate Esters, and Phosphate Anhydrides

The Chemistry of the Aromatic Heterocycles and Nucleic Acids

Amino Acids, Peptides, and Proteins

Pericyclic Reactions

Filters

Give the structure of the nucleophile that would react with benzyl chloride (PhCH₂Cl) to give the sulfonium salt:

cis-3-Hexene is treated with OsO₄ (osmium tetroxide), then water. Which one statement is true about the product?

In the S_N2 reaction, sulfur is the "leaving atom" in the leaving group. The products are a single sulfide (R-S-R´) and a single ether. a. Draw the structures of the products in the appropriate boxes. b. On the reaction, draw the curved-arrow notation for this reaction.