10/1

Question 1

what is the gringard reagent characterized by?

Answer 1

a carbon magnesium bond that reverses polarity and creates a carbocation like molecule that can act as a nucleophile and a base

Question 2

how are organolithium and the gringard reaction similar

Answer 2

they have the same mechanistic pathway and both act as nucleophiles

Question 3

what is needed to form an organo lithium

Answer 3

an alkyl halide, 2 equivalents of lithium, and and ether solvent like Et2O (Diethyl Ether)

Question 4

what is the order of reactivity for alkyl halides to make grignards or organolithiums

Answer 4

RI>RBr>RCl

Question 5

what is it called when the halogen is exchanged with magnesium in an alkyl halide

Answer 5

magnesium halogen exchange

Question 6

what solvents do you use in grignard reagents?

Answer 6

ether (diethyl ether Et2O), THF, or hexane
do not use water or polarprotic solvents as it can undergo acid base chemistry

Question 7

why can you not use grignards or organolithium’s in a water solvent

Answer 7

Grignard reagents are nucleophilic and basic so they can undergo strongly favored acid-base chemistry

Question 8

what is the dual nature of nucleophiles

Answer 8

they can be nucleophilic and basic

Question 9

which way will equilibrium lie in an acid base reaction with an organometallic and water

Answer 9

it will favor the formation of the weaker acid, which is R-H and OH

Question 10

how does an aldehyde and ketone react with a Grignard reagent?

Answer 10

it undergoes nucleophilic addition once to create an alcohol

Question 11

how does an ester react with a grignard

Answer 11

it reacts with two equivalents to form a tertiary alchohol

Question 12

what are good sources of protons for the protonation of an alkoxide ion

Answer 12

H3O+ or NH4Cl

Question 13

if you have a carbonyl and an alcohol on a chain, how can you isolate it so the organometallic nucleophile will attack the carbonyl and not deprotonate the alcohol

Answer 13

use a protecting group like TBSCl

Question 14

what is a conjugated system

Answer 14

they are molecules where there is a chain of alternating single and double bonds that allows for the delocalization of pi electrons across overlapping p-orbitals

Question 15

what are the features of a conjugated system

Answer 15

each carbon is sp2 and there is a p-orbital above and below the plane that allows electrons to be delocalized as the electron density can be evenly shared throughout

Question 16

what is a spacer carbon

Answer 16

it is a sp3 carbon in between two pi bonds that interrupts the conjugated system, the electrons are localized and this is an nonconjugated system

Question 17

what is considered a conjugated system

Answer 17

a system with sp2 carbons in an uninterrupted array

Question 18

what is an allyl radical, is it conjugated

Answer 18

it is a radical, next to a double bond. It is conjugated because all the carbons are sp2

Question 19

what is an allyl cation? Is it conjugated

Answer 19

an allyl cation is a carbocation next to a double bond, it is conjugated because all carbons are sp2

Question 20

whats an enyne

Answer 20

it is a conjugated alkyne

Question 21

can sp carbons have conjugation

Answer 21

yes

Question 22

when reacting an alkene with a halogen X2 in low temperatures, what occurs

Answer 22

electrophillic addition

Question 23

when reacting an alkene with a halogen X2 in a high temperatures, what is the result

Answer 23

a radical substitution where the allylic hydrogen is replaced with a halogen

Question 24

what pathway does an allylic substitution go through

Answer 24

under high temperatures, allylic substitution of the hydrogen on an allylic carbon is replaced with a halogen through a radical mechanism with a allylic radical

Question 25

what is the order of stability for a radical

Answer 25

allylic radicals are the most stable

3>2>1

vinyl radicals are the least stable

Question 26

why is it better to use NBS to preform allylic substitution rather than Br2 or Cl2

Answer 26

it is a solid while Bromide and Chlorine are liquid and gas.

It also gives you the desired product

Question 27

what is needed to preform allylic bromination on propene

Answer 27

NBS serves as a source of bromine radical, hv (light), and peroxides which serve as a radical initiator