Exam 2 Material

Question 1

3 ways to prepare alcohols via reduction

Answer 1

1. Hydrogenation (H2, Pd) add a hydrogen to the oxygen and a hydrogen to the carbon. WILL REDUCE EVERY PI BOND!!!
2. Sodium borohydride (NaBH4, MeOH) donates hydride. ONLY WILL REDUCE DOUBLE BONDED C-O.
3. Lithium aluminum hydride (LiAl4 or LAH, H2O) NEED TO BE DONE IN SEPARATE STEPS!! same mechanism as borohydride… ONLY REDUCES DOUBLE BONDED C-O.

All reduce a ketone to an alcohol.

Question 2

Which will reduce carboxylic acids and esters?

Answer 2

LAH because it is more reactive. not NaBH4

Question 3

Prepare alcohols by Grignard reagent

Answer 3

(Made by alkyl halide with mg + ether) R-Mg-X

• puts a Mg between the carbon and the halogen.
• carbon withdraws electrons from bond by it is more electronegative than Mg, therefore it acts as the nucleophile.
• Grignard reagents react with aldehydes and ketones to form alcohols with the addition of an R group on the same carbon.