Chapter 17, Problem 17.74P

Interpretation Introduction

Interpretation:

Structures of compounds A-J in the given reaction sequence are to be determined.

Concept introduction:

Phosphorous tribromide ${\text{(PBr}}_{\text{3}}\text{)}$ can convert primary and secondary alcohol to alkyl halide via back-to-back ${\text{S}}_{\text{N}}\text{2}$ reactions.

Potasium cynide (KCN) can substitute Br by cynide group.

Lithium aluminum hydride $\left({\text{LiAlH}}_{\text{4}}\right)$ and sodium borohydride $\left({\text{NaBH}}_{\text{4}}\right)$ are sources of hydride ${\text{(H}}^{\text{-}})$ used to reduce aldehyde and ketone in the protic solvent.

The Hofmann elimination reaction leads to an anti-Zaitsev elimination product or Hofmann product. An amine with a poor leaving group is converted to a tetraalkyl ammonium ion, which has a moderately good leaving group, using excess of an alkyl halide like ${\text{CH}}_{\text{3}}\text{I}$. Subsequent treatment is followed by heat which induces elimination.

Sodium hydride (NaH) is an ionic hydride, and thus a strong base, but it is not nucleophilic.