Chapter 17, Problem 17.5YT

Interpretation Introduction

Interpretation:

Suitable mechanism for reaction in Equation $\text{17-4 }$ and Equation $\text{17-5 }$ is to be determined.

Concept introduction:

The hydride anion, ${\text{H:}}^{\text{-}}$, is a hydrogen atom with an extra electron. (It is usually further abbreviated to ${\text{H}}^{\text{-}}$.) Unlike such species as ${\text{Cl}}^{\text{-}}$ and ${\text{HO}}^{\text{-}}$, however, ${\text{H}}^{\text{-}}$ does not exist on its own at any appreciable concentration in a solution because it is extremely reactive, both as a nucleophile and as a base, even reacting with many common solvents. ${\text{H}}^{\text{-}}$ has two common hydride sources in organic chemistry – sodium borohydride (${\text{NaBH}}_{\text{4}}$) and lithium aluminum hydride (${\text{LiAlH}}_{\text{4}}$ or $\text{LAH}$). It is so reactive because it is small in size and its nucleus is only moderately electronegative, so it does not accommodate the negative charge well.