diels alder

Question 1

what’s the pattern of a diels alder

Answer 1

break 3 pi bonds, form 2 single bonds and a pi bond

Question 2

How many pi electrons are involved in diels alder

Answer 2

6

Question 3

what is the conformation requirement for a diels-alder reaction

Answer 3

the pi bonds must be in the s-cis conformation

Question 4

which conformation of a diene is more stable? s-cis or s-trans? which way does the equilibrium lie

Answer 4

s-trans is more stable due to the steric effects seen in s-cis, equilibrium favors s-trans as it is lower energy

Question 5

how many pi electrons are in the diene

Answer 5

4

Question 6

how many pi electrons are in the dienophile

Answer 6

2

Question 7

how do the 6 pi electrons in a diels alder react

Answer 7

in a concerted mechanism

Question 8

how many carbon carbon bonds are made in a diels alder reaction

Answer 8

2

Question 9

what does the diels alder reaction ALWAYS make?

Answer 9

six membered ring

Question 10

what type of reaction is a diels alder?

substitution
addition
rearrangement

Answer 10

addition

Question 11

what is the product of a diels alder called

Answer 11

a adduct

Question 12

what in the transition state for a diels alder reaction makes it occur readily at room temperature

Answer 12

the moving of 6 pi electrons creates a transition state that closely resembles the resonance hybrid, this makes the energy very low and the product forms readily at room temperature

Question 13

what is the normal demand for a diels alder reaction defined by

Answer 13

the diene has an electron donating group and the dienophile has a electron withdrawing group

Question 14

what is the effect of having an EDG on a diene

Answer 14

it brings the energy up

Question 15

what is the effect of having an EWG on the dienophile

Answer 15

it brings the energy down

Question 16

what is the inverse diels alder reaction defined by

Answer 16

the diene has an electron-withdrawing group and the dienophile has an electron-donating group

Question 17

What is an electron donating group

Answer 17

electron donating groups are electron rich like an ether or alchohol

Question 18

why is cyclopentadiene highly reactive

Answer 18

it forces the diene to be cis

Question 19

what are electron withdrawing groups

Answer 19

anything that pulls electrons towards itself

halogens or carbonyls

Question 20

where is the bridgehead carbon in bicyclic adduct from a diels alder

Answer 20

it is above the plane

Question 21

what is the endo product

Answer 21

it is the kinetic product, it has a more stable transition state and is formed in cooler temperatures

it is higher energy due to the concave nature

the substituents are pointed down

Question 22

what is the exo product

Answer 22

it is when the groups are pointed externally and up (wedge), the product is more stable since there are less steric interactions

this product is thermodynamically favored

Question 23

what product forms at 0°C for diels alder?

Answer 23

the kinetic endo product with the groups pointing down

Question 24

what product forms at 40°C for the diels alder

Answer 24

the thermodynamic exo product with the groups pointing externally out

Question 25

what is the stereoisometric relationship between the endo and exo product

Answer 25

they are diastereomers

Question 26

what type of reaction is the diels alder in relation to stereochemistry

Answer 26

it retains stereochemistry

Question 27

what is the difference between stereoselective and stereospecific

Answer 27

stereoselective is the favoring of a certain stereoisomer

stereospecific is a chemical reaction where the stereochemistry of the reactants directly determines the stereochemistry of the products