fun facts 2

Question 1

E2 general scheme

Answer 1

1 step

base attacks H
double bond forms

Question 2

rate law for E2

Answer 2

bimolecular elimination
rate : k (subs) (base)

Question 3

free energy diagram for E2

Answer 3

one hill
sm (2)
transition state (dotted line )
products (3)

Question 4

unique thing about E2 reactions

Answer 4

stereo electronic requirement

H removed must be anti peri planar (think of waterfall in AS + newman projection, must be on beta carbon and pointing 180 away) - staggered anti conformation

Question 5

why is e2 stereo electronic

Answer 5

to allow zaitzefs product : more substituted alkene

so the CH sigma bond is parallel to empty C -LG sigma star orbital

less energy in newman projection if they’re spaced out

Question 6

what do big bases like t-BuO- do to e2 reactions

Answer 6

form the hoffman product
less substituted alkene

cant get to the anti peri planar H due to steric hinderance

Question 7

what isomer is usually favoured in e2

Answer 7

e isomer ( diff sides)
then z isomer
then hoffman product

Question 8

how is e2 stereospecific

Answer 8

diff diastereomers form diff isomers
eg : 1 makes E, 1 makes Z

Question 9

e2 and stereoelectronic with benzene and chairs

Answer 9

normally if groups are equatorial, there is no antiperi planar H.

the groups must be axial

Question 10

what type of substrate do E2 reactions prefer

Answer 10

3 will never happen with methyl subs

Question 11

e2 and sn2 fight :
tertiary subs
NaOMe
Acetone

Answer 11

E2 only

Question 12

e2 and sn2 fight:
2 subs
NaOMe
acetone

Answer 12

mostly sn2
a lot of e2 aswell

Question 13

e2 cheat sheet

Answer 13

1 step
stereo electric
stereospecific
3, allylic, benzylic subs
strong bronsted lowry base
wide range of solvent
good lg

Question 14

strong bronsted lowry bases for e2

Answer 14

RO-
R2N-
H-
t-BuO-

Question 15

E1 reaction general scheme

Answer 15

loss of lg
cc+
attack of H
double bond formed

Question 16

free energy diagram for e1

Answer 16

2 hills
sm
intermediate
products

Question 17

e1 and product formation

Answer 17

zaitzefs product
more substituted alkene&raquo_space;

E is favoured over Z

Question 18

what is with sterospecific and e1

Answer 18

it’s not stereospecific

u don’t rotate the diastereomer to form diff E/Z products.

they both give the same isomer

Question 19

what type of bases or nucs do SN1 prefer

Answer 19

weak bases: R2NH
acids: HCl, H2SO4, H3PO4

Question 20

E1 cheat sheet

Answer 20

2 steps
regio + stereoselective (Z rule)
3, allylic, benzylic, alpha heteroatom
polar PROTIC
weak base or acid
good lg

Question 21

E1CB

Answer 21

unimolecular elimination conjugate base

• bad lg
• strong base
  attack of H, conjugate - to carbonyl group

conjugate - back to bad lg

Question 22

what does allylic mean

Answer 22

Carbon bonded to a double bond

Question 23

what does benzylic mean

Answer 23

Carbon bonded to a benzene

Question 24

what is an alpha heteroatom substrate

Answer 24

carbon bonded directly to a heteroatom
(not c or h )