Alkenes, Alkynes, And Elimination Reactions

Front 1

Elimination reactions commonly occur via the removal of ___ or ___?

Back 1

alcohols, alkyl halides

Front 2

What are the two types of elimination?

Back 2

E1, E2

Front 3

In the second step of E1, a proton on the beta carbon is removed by...?

Back 3

a weak base

Front 4

Higher temperatures tend to favor ___ over ___?

Back 4

E1, Sn1

Front 5

As a strong base removes a proton, a halide located ___ to the proton leaves, resulting in the formation of a double bond

Back 5

anti

Front 6

E2 reactions will often have ___ possible products, but the ___ substituted double bond will make up the larger percentage of the products

Back 6

two, more

Front 7

A ___base favors E2 over Sn2

Back 7

stronger

Front 8

Weak Lewis bases, aka ___ ___, favor ___ over ___

Back 8

strong nucleophiles, Sn1, E2

Front 9

T/F cyanide (CN-) and iodide (I-) are strong nucleophiles/ poor bases

Back 9

true

Front 10

A strong base will pull off a ___ hydrogen before it can reach the ___ carbon atom of the substrate, resulting in an E2 reaction

Back 10

beta, alpha

Front 11

With the help of a metal catalyst, alkenes can be reduced in a process known as ___ ___

Back 11

catalytic hydrogenation

Front 12

Typical metal catalysts include ___, ___, and ___

Back 12

platinum, palladium, nickel

Front 13

Catalytic hydrogenation has what type of addition?

Back 13

syn

Front 14

Reactions where only one stereoisomer is formed are called ___ reactions

Back 14

stereospecific

Front 15

A chemical reaction is ___ when a certain stereoisomer or set of stereoisomers predominate as products.

Back 15

stereoselective

Front 16

A reaction is ___ if different isomers lead to isomerically opposite products

Back 16

stereospecific

Front 17

The electrons in the double bond act as a Lewis ___ and react with the partially ___ hydrogen of HX molecules

Back 17

base, positive

Front 18

In an HX addition if the alkene is assymetrical the intitial protonation occurs at which carbon?

Back 18

the least substituted/ the one with the most protons

Front 19

To test for the presence of double bonds, sometimes a ___ ___ is used

Back 19

diatomic halogen

Front 20

The double bonds of alkenes can act as ___

Back 20

nucleophiles (b/c the electrons of the pi bond are particularly reactive, so they are easily attacked by Lewis acids

Front 21

The first step of the addition of the diatomic halogen results in ___ ___ ___

Back 21

cyclic halonium ion

Front 22

In diatomic halogen addition, the double bond attacks the ___ ___, with the ___ ___ acting as a ___ ___

Back 22

diatomic halogen, second halogen, leaving group

Front 23

The two halogens that are known to make cyclic halonium ions are...

Back 23

chlorine and bromine

Front 24

In diatomic halogen addition reactions the X- attacts the ion via ___ addition

Back 24

anti

Front 25

Water can added to alkenes under what kind of conditions?

Back 25

acidic (most commonly H2SO4)

Front 26

Addition of water must be completed at ___ temperatures

Back 26

low

Front 27

Hydration of the double bond can also be achieved under mild conditions with ___ ____

Back 27

oxymercuration-reduction

Front 28

Free-radical additions occure in the presence of ___, ___, or ___

Back 28

peroxides, oxygen, UV light

Front 29

Do free-radical additions obey or disobey Markovnikov's rule?

Back 29

no

Front 30

In free radical additions the halogen ends up on the ___ subsituted

Back 30

least

Front 31

In free radical additions the ___ adds first to the double bond

Back 31

X "dot"

Front 32

Free radical addition to alkenes is most useful for which halogen(s)?

Back 32

bromine

Front 33

Hydroboration occurs because ___ adds readily to double bonds

Back 33

diborane (B2H6)/ borane (BH3)

Front 34

The boron atom is a ___ ___ and attaches to the ___ sterically hindered carbon atom. At the same time, a ___ is transferred to the ___ carbon

Back 34

Lewis acid, less, hydride, adjacent

Front 35

The second step of hydroboration is an ___ ___ with ___ and ___ ___ that directly transfers ___ to the bond with boron producing an ___ with overall ___ ___, ___ orientation

Back 35

oxidation-hydrolysis, peroxide, aqueous base, water, alcohol, anti-Markovnikov, syn

Front 36

Alkenes can be oxidized with KMnO4, if it is ___, ___, and ___, the product has ___ added to ___. They have ___ addition.

Back 36

cold, dilute, basic, -OH, each side of the double bond, syn

Front 37

A ___, ___ solution of KMnO4 followed by ___ on nonterminal alkenes, they are cleaved to form ___ ___ ___ of ___. Terminal alkenes cleave to form a ___ and ___.

Back 37

hot, basic, an acid wash, two molar equivalents, carboxylic acid, carboxylic acid, carbon dioxide

Front 38

If the nonterminal double-bonded carbon is disubstituted, a ___ will be formed.

Back 38

ketone

Front 39

Ozonolysis will only cleave the double bond in half to become a ___ under reducing conditions. It will become a ___ is the starting molecule is disubstituted.

Back 39

aldehyde, ketone

Front 40

Ozonolysis under ___ conditions yields the same products as hot, acidic KMnO4

Back 40

oxidizing

Front 41

To obtain alcohols from ozonolysis, we have to ___ the aldehyde or ketone products with a mild ___ agent, such as NaBH4 (sodium borohydride) or the more potent LiAlH4

Back 41

reduce, reducing

Front 42

Alkenes can be oxidized with peroxycarboxylic acids such as peroxyacetic acid (CH3CO3H) and m-chloroperoxybenzoic acid (MCPBA). The products of these reactions are ___ aka ___. This reaction is an example of ___ addition

Back 42

epoxides, oxiranes, syn

Front 43

Polymerization requires ___ temperatures and ___. It usually occurs through a ___ mechanism.

Back 43

high, pressure, radical

Front 44

___ have larger dipole moments than ___.

Back 44

alkynes, alkenes

Front 45

Terminal alkynes are fairly ___. This means that terminal alkynes can stabilize ___ charge fairly well.

Back 45

acidic, negative

Front 46

One way to make triple bonds is through two rounds of ___ of a geminal or vicinal ___.

Back 46

elimination, dihalide

Front 47

A more useful method is to add an existing triple bond to a ___ carbon skeleton.

Back 47

new

Front 48

Terminal triple bonds can be converted to nucleophiles by removing its acidic proton with a ___ ___, such as ___ or ___

Back 48

strong base, NaNH2, n-BuLi

Front 49

What catalyst will stop an alkyne reduction from going to alkane? What is this catalyst made of?

Back 49

Lindlar's, palladium on barium sulfate with quinoline

Front 50

Lindlar's catalyst reactions have ___ addition because...

Back 50

syn, they occur on a metal surface

Front 51

Sodium in liquid ammonia is used to ___ alkynes to ___.

Back 51

reduce, alkenes

Front 52

Free radical addition to alkynes is also ___ ___, with the product usually being the ___ isomer

Back 52

anti-Markovnikov, trans

Front 53

Hydroboration of alkynes uses ___ addition, and what atom adds first?

Back 53

syn, boron

Front 54

When dealing with terminal alkynes, a ___ borane is used to prevent further boration of the vinylic intermediate to an ___.

Back 54

alkane

Front 55

Alkynes and alkens have the same products when reacted with what type of KMnO4?

Back 55

hot, basic

Front 56

When alkynes are reacted with ozone they yield ___ or ___. Terminal alkynes produce ___.

Back 56

carboxylic acid, CO2, CO2

Front 57

Cleavage of a primary double bonded carbon yields a ___. While cleavage of a secondary double bonded carbon results in a ___.

Back 57

carboxylic acid, ketone

Front 58

BH3/THF added to an terminal alkyne will produce ___ and ___ with internal alkynes.

Back 58

aldehydes, ketones