Chapter 15

Question 1

organometallic

Answer 1

bond between a metal and carbon

-changes polarity of carbon (slightly + becomes slightly -)

Question 2

Grignard reagents

Answer 2

an organomagnesium compound, prepared by addition of an alkyl, aryl, or alkenyl halide to Mg metal in diethyl ether or THF
-dissolve as coordination compounds solvated by ether

Question 3

what is an alternative to Grignard reagents?

Answer 3

Alkyl lithiums

Question 4

carbon-metal bonds in RMgX and RLi are best described as….

Answer 4

polar covalent

Question 5

carbanion

Answer 5

an anion in which carbon has an unshared pair of e- and bears a - charge
-great nucleophiles

Question 6

limitations to carbanion

Answer 6

• can’t make grignards w/ acidic or electrophilic functional groups
• can’t do simple SN2 using alkyl halides; E2 dominates

Question 7

Grignard reagent reacts with formaldehyde to give

Answer 7

primary alcohol

Question 8

Grignard reagent reacts with aldehydes to give

Answer 8

secondary alcohols

Question 9

Grignard reagents react with esters to give

Answer 9

tertiary alcohols

Question 10

Grignard reagents react with ketones to give

Answer 10

tertiary alcohols

Question 11

Grignard reagents react with epoxides to give

Answer 11

primary alchols

Question 12

epoxides

Answer 12

illustrate how many common organic functional groups contain electophile carbons

Question 13

matchmaker-homewrecker steps

Answer 13

1. find the +, find the -, then hook them together (arrows from - to +)
2. look for alternative negative or positive partners
3. we are considering RMgX and RLi as our partial - (neg = nucleophile) the search is for the partial pos

Question 14

addition of a nucleophile to carbonyl group

Answer 14

• racemic mixture produced
• often tetrahedral product with a new chiral center
• if none of the starting materials is chiral and the rxn takes place in an achiral environment, the enantiomers will be formed as a racemic mixture
• new C-C bond formed

Question 15

Gilman reagents

Answer 15

• lithium diorganocopper reagents
• prepared by treating an alkyl, aryl, or alkyl, or alkenyl Lithium compound with Cu(I) Iodide
• use less electrophilic metal = less reactive
• rules of SN2 mechanism no longer hold
• add Cu(I) salt to RLi

Question 16

coupling Gilman with a vinyl halide

Answer 16

is stereospecific, configuration of c-c double bond is restrained

Question 17

Gilman reagent + epoxide

Answer 17

ring opening is stereoselective

Question 18

carbene

Answer 18

• (R2C); a neutral molecule in which a carbon atom is surrounded by only 6 valence electrons
• in its lowest energy state, carbon is sp2 hybridized w the unshared pair of electrons occupying the 3rd sp2 orbital

Question 19

simmon-smith reaction

Answer 19

• way to add methylene to an alkene to form a cyclopropane
• generation of Simmons-smith reagent
• CH2i ICH2ZnI
• concerted mechanism (happens all at once)