Organic Chemistry

Front 1

beta elimination

Back 1

a reaction in which a halide and a hydrogen on the neighboring (beta) carbon are removed
a reaction in which a molecule, such as hcl hbr hi or hoh, is split out or eliminated from adjacent carbons

Front 2

nucleophile

Back 2

this refers to nucleus loving. it is a molecule or ion that donates a pair of electrons to form a new covalent bond

Front 3

what are the two competing reaction sin this chapter

Back 3

nucleophilic substitution and beta elimination

Front 4

in nucleophilic susbstitution what happens if the nucleophile is negatively charged

Back 4

then in a substitution reaction the atom donating the electron will become neutral

Front 5

what happens if the nucleophile is not charge din nucle substitution reaction

Back 5

the atom donating the atom will become positively charged in the product

Front 6

what are the two mechanisms for nucleophilic substitution?

Back 6

sn1 and sn2

Front 7

what is the major difference between sn1 and sn2

Back 7

the timing of bond breaking between carbon and the leaving group and of bond forming between carbon and the nucleophile`

Front 8

bimolecular reaction

Back 8

reaction that involves two species are involved in the rate determining step

Front 9

sn2

Back 9

substitution nucleophilic bimolecular reaction
bond braking and bonding occur simultaneously
nucleophile attacks from opposite side of the leaving group(backside attack)

Front 10

why is it better to attack from the back side

Back 10

it assists in breaking the leaving group bond, and populate the antibonding molecular orbital of the same bond

Front 11

sn1

Back 11

substitution nucleophile unimolecular reaction
the breaking of the leaving group is entirely completed before the forming of the nucleophile begins

Front 12

unimolecular reaction

Back 12

reaction in which only one species is involved in the rate-determining step

Front 13

what mechanism is rate dependent on the concentration of haloalkane and wich one is dependent on both haloalkane and nucleophile

Back 13

sn1 is dependent on concentration of haloalkane and sn2 is dependent on concentration of haloalkane and nucleopile

Front 14

explain the sn 1 stereochemistry
on a chiral center****

Back 14

attack on the right side gives the s - enantiomer
attack on the left side gives the r -enantiomer

Front 15

explain the stereochemistry of sn2

Back 15

inversion of configuration when reacted by the nucleophile

Front 16

what special satbilizatioon allos 1 degree haoalkanes ti undergo sn1

Back 16

allylic carbocations

Front 17

allylic carbocations

Back 17

carocation in which an allylic carbon bears the positive charge
they are more stable than alkyl carbocations

Front 18

what makes a good leaving group

Back 18

a good living group will be the most stable anion, and therefore the weak conjugate bases of strong acids

Front 19

protic solvent

Back 19

a solvent that is a hydrogen bond donor; the most common contains -oh groups

Front 20

aprotic solvent

Back 20

a solvent that cannot serve as a hydrogen-bond donor

Front 21

why does a sn1 reaction need a solvent?

Back 21

since sn1 requires creation and separation of opposite charges so a protic solvent would help in keeping the charges separated

Front 22

why does a sn2 reaction need a solvent

Back 22

since the solvation of nuclephile has to be stronger so it wont beremoved from the shell to reach the transition state
aprotic solvents solvate cations but not anions thus how they help
but it could also use the protic sovent

Front 23

nucleophilicity

Back 23

a kinetic property measure by the rate at which a nucloephile causes nucleophilic substitution on a reference compound under a standard set of experimental conditions

Front 24

what makes a good nucleophile?

Back 24

a strong base
there is a trend between basicity and nucleophilicity
pka higher than 11 than strong nucleophile about 11 moderate and less than weak

also depends on solvent ad shape not just basicity

Front 25

explain the solvation effects of nucleophilicities

Back 25

the stronger interaction with the solvent the weaker the nucleophile
in aprotic solvents solvate cations so anions are freer and participate readily in nucleophilic substitution

in protic solvents there is a degree of reversal cuz it solvates the anions and make the weakest bases the strongest nucleophiles

Front 26

how does the shape of the nucleophile affect its strength

Back 26

if they are shaped like a bullet or spear that can better penetrate thus making them better nucleophiles

Front 27

what mechanism will a methyl alkyl halide undergo?

Back 27

sn2, because sn1 would be so unstable and not observed in solution

Front 28

what mechanism will be favored if we have a primary alkyl halide?

Back 28

sn2 will be favored , because they are so unstable

Front 29

what mechanism will be favored if we have a secondary alkyl halide?

Back 29

sn2 favored in aprotic solvents with good nucleophiles
sn1 favored in protic solvents with poor nucleophiles rearrangements may occur

Front 30

what mechanism will be favored if we have a tertiary alkyl halide?

Back 30

sn1 is favored cuz of the ease of formation of tertiary carbocation, and sn2 does not occurs cuz of steric

Front 31

what are the beta elimination mechanism

Back 31

e1 and e2

Front 32

what is the similar way of steroreoselecticvity as in sn2 the same as e2

Back 32

anti coplanar arrangement

Front 33

meso isomer in e2 reaction gives what?

Back 33

this gives a (e) conformation

Front 34

racemic isomer in e2 reaction gives what?

Back 34

this gives a (z) conformation

Front 35

what mehanism would be better for an alkyl primary halide

Back 35

e2 because elimination is observed and requires sterically hindered strong base

Front 36

what mechanism would be better for an alkyl secondary halide

Back 36

e1 with weak bases and e2 with strong bases

Front 37

what mechanism would be better for an alkyl tertiary halide

Back 37

e1with weak bases and e2 with strong bases

Front 38

give common protic solvents

Back 38

water, hcooc( formic acid), methanol (ch3oh), ethanol (ch3ch2oh), acetic acid (ch3cooh)

Front 39

what makes a polar solvent

Back 39

dielectric constant of 15 or greater

Front 40

what makes a nonpolar solvent

Back 40

dielectric constant of less than 5

Front 41

give common aprotic solvents

Back 41

acetone (ch3coch3)

Front 42

what is Zaitsev’s rule

Back 42

rule that states that the major product of a beta elimination reaction is the most stable alkene, the alkene with the greatest number of substituents on the carbon-carbon double bond