Question

1. Compare the use of sodium borohydride versus lithium aluminum hydride in terms of handling and usage.

2. Be able to decide when to use sodium borohydride and when to use lithium aluminum hydride for reducing an aldehyde.

Answer 1

1) NaBH₄ is preferred for aldehydes and ketones because it does not react violently with H₂O, the way LiAlH₄ does and can be used as an aqueous solution, whereas the LiAlH₄ must be delivered in an anhydrous solution of diethyl-ether, Et₂O, and then neutralized by water and acid to isolate the product/s.

Reduced by LIATH Reduced by NaBH R o ROR RRR H Ease of reduction

2)

NaBH, is More Selective OH O hoben wir 1) NaBH4 2) H307 OH OH 1) LIAIH 2) H30* OH