Organic Chemistry - Ethers, Epoxides, Thiols, And Sulfides (Ch. 18)

Front 1

Thiols (R-S-H) and sulfides (R-S-R') are sulfur analogs of _____ and _____ respectively.

Back 1

alcohols, ethers

Front 2

Williamson ether synthesis involves:

Back 2

alkoxide ion reacting with primary halide or tosylate in an SN2 reaction

Front 3

Unsymmetrical ethers should be synthesized by the ___ hindered alkoxide partner and the ____ hindered halide partner.

Back 3

more, less

Front 4

Reagents used in alkoxymercuration reaction of adding alcohol to alkene to produce an ether

Back 4

1. (CF3CO2)2Hg, R-OH
2. NaBH4
(Markovnikov addn)

Front 5

Ethers with primary and secondary alkyl groups are cleaved into a single alcohol and single alkyl halide by an ___ mechanism

Back 5

SN2

Front 6

Ethers with tertiary, benzylic, or allylic groups cleave by ___ or ___ mechanisms because these substrates can produce stable ____ ______

Back 6

SN1, E1
intermediate carbocations

Front 7

Heating an allyl aryl ether to 200-250 degrees Celsius results in:

Back 7

Claisen rearrangement (o-allylphenol)

Front 8

Used to convert alkene into a 1,2-epoxy-alkane

Back 8

1. Cl2 in H2O
2. NaOH in H2O

Front 9

Used to convert epoxide into trans-1,2-diol

Back 9

H3O+

Front 10

Used to convert epoxide into trans-1,2-haloalcohol

Back 10

HX in ether

Front 11

When epoxide carbon atoms are either primary or secondary, attack of nucleophile occurs at primarily the ___ highly substituted site

Back 11

less

Front 12

When one of the epoxide carbons is tertiary, nucleophilic attack occurs primarily at the ____ highly substituted site.

Back 12

more

Front 13

Ethers can only be cleaved by:

Back 13

strong acids (except for HCl)

Front 14

Base-catalyzed epoxide opening is an SN2 reaction in which attack of the nucleophile takes place at the ___ hindered epoxide carbon.

Back 14

less

Front 15

Crown ethers are named according to the format:

Back 15

x-crown-y, where x is the total # of atoms in the ring and y is the # of oxygen atoms

Front 16

The importance of crown ethers derives from their extraordinary abiity to:

Back 16

solvate metal cations by sequestering the metal in the center of the polyether cavity

Front 17

The -SH group is referred to as the:

Back 17

mercapto group

Front 18

Thiols are usually prepared from alkyl halides by using:

Back 18

sulfur nucleophile such as hydrosulfide anion (-SH)

Front 19

Thiols can be oxidized by Br2 or I2 to yield:

Back 19

disulfides (R-S-R')

Front 20

Disulfides can be reversed back into thiols by using:

Back 20

zinc, H+

Front 21

Treatment of a thiol with a base gives the corresponding ____ ion

Back 21

thiolate (RS-)

Front 22

Unlike dialkyl ethers, dialkyl sulfides are good nucleophiles that react rapidly with primary alkyl halides by SN2 mechanism to produce _____ ions.

Back 22

sulfonium (R3S+)

Front 23

Treatment of a sulfide with H2O2 at room temperature yields ____.

Back 23

sulfoxide (R2SO)

Front 24

Oxidation of sulfoxide with a peroxyacid yields ____.

Back 24

sulfone (R2SO2)

Front 25

The sulfoxide that is used as a polar aprotic solvent is:

Back 25

DMSO (dimethyl sulfoxide)

Front 26

Ethers show an IR absoprtion due to C-O single-bond stretching in the range:

Back 26

1050-1150 cm-1

Front 27

Hydrogens on carbon next to an ether oxygen show HNMR absorptions in the region:

Back 27

3.4-4.5 sigma

Front 28

Ether carbon atoms have chemical shifts in the CNMR spectrum in the ______ sigma range

Back 28

50 to 80