E2

Question 1

Hs removed by the base must be

Answer 1

antiperiplanar

think of newman projection
beta carbon, facing other way

Question 2

if there are 2 Hs on the beta carbon then the mechanism is

Answer 2

stereoselective

mainly E isomer

Question 3

if there is 1 H on the beta carbon

Answer 3

stereospecific

only E isomer

Question 4

E2 with cyclohexane, what must the 2 groups ( CX and CH be)

Answer 4

both axial

no anti peri planar Hs when X is equatorial.

unstable chair conformation meaning this reaction is slow. not many are arranged with the large group axial.

Question 5

hofmann elimination

Answer 5

less substituted alkene product
large base forms it
still antiperiplanar, but the H that sticks out more on the edge (leading to less substituted product)

Question 6

zaitzef elimination

Answer 6

small base makes it
more substituted alkene
still anti peri planar but the H that will form the more substituted alkene product