Chapter 7, Problem 7.18P

Interpretation Introduction

(a)

Interpretation:

The appropriate curved arrows and reaction products are to be drawn for each of the given carbocation undergoing a $\text{1, 2-hydride}$ shift.

Concept introduction:

A $\text{1, 2-hydride}$ shift involves a hydrogen atom attached to a carbon adjacent to a carbocation. The hydrogen atom shifts to the carbocation along with its bond pair, i.e., as a hydride ion ${\text{H}}^{\text{-}}$. This shift amounts to a rearrangement of the carbocation. The numbering in the shift simply indicates that the hydride ion has moved from one carbon to an adjacent one and is not the same as that used in the IUPAC nomenclature.

Interpretation Introduction

(b)

Interpretation:

The appropriate curved arrows and reaction products are to be drawn for a $\text{1, 2-methyl}$ shift in the given carbocation.

Concept introduction:

A $\text{1, 2-methyl}$ shift involves a methyl ($-{\text{CH}}_{\text{3}}$) group attached to a carbon adjacent to a carbocation. The methyl group shifts to the carbocation along with its bond pair. This shift amounts to a rearrangement of the carbocation. The numbering in the shift simply indicates that the hydride ion has moved from one carbon to an adjacent one and is not the same as that used in the IUPAC nomenclature.