organometallic nucleophiles and acetylides

Question 1

acetylide

Answer 1

H-C - triple bond - C: -

used as a nucleophile

Question 2

acetyline

Answer 2

H-C - triple bond - C-H

fairly acidic (conjugate base is pretty stable from sp hybridization)

Question 3

what are organometallic nucleophiles?

Answer 3

• nucleophiles made from highly oxidizable metals (Li, Na, Mg) and reducible organohalides (Br)

Question 4

making organometallic nucleophiles

Answer 4

• Carbon has partial + charge in organohalide
• Carbon gains partial - charge (reduced) after bonding to metal

Question 5

running the reaction to make organometallic nucleophiles

Answer 5

• must use aprotic solvents–R group with C is a carbanion which is a very strong base and will react with protons
• reactions use Argon (no air) and are cooled to slow reaction since bases are so strong

Question 6

Grignard reagents

Answer 6

organomagnesium nucleophiles
- C in R group is electron donor
- Mg acts as a spectator ion (not really relevant in mechanism)

Question 7

using Grignard reagents with different carbonyl compounds

Answer 7

• attacks ketones and aldehydes once
• attacks esters twice
• does not react with carboxylic acids or amides (protons)