Chapter 28, Problem 28.24P

Interpretation Introduction

(a)

Interpretation:

Each of the following compounds exists as a fluxional molecule that is interconverted into one or more identical forms by the sigmatropic process indicated. One structure in each case that demonstrates the process involved is to be drawn. Each process is an allowed pericyclic reaction – the statement is to be verified.

Concept introduction:

When a molecule undergoes a dynamic molecular motion involving the interchange of two or more groups which are chemically and magnetically different, then the molecule is said to have fluxionality nature. In this case, the signals corresponding to interchanged two or more groups will be identical, if the rate of exchange of the groups occurs very quickly. The fluxionality in organic molecules can be easily followed by multinuclear NMR spectroscopy.

Interpretation Introduction

(b)

Interpretation:

Each of the following compounds exists as a fluxional molecule that is interconverted into one or more identical forms by the sigmatropic process indicated. One structure in each case that demonstrates the process involved is to be drawn. Each process is an allowed pericyclic reaction – the statement is to be verified.

Concept introduction:

When a molecule undergoes a dynamic molecular motion involving the interchange of two or more groups which are chemically and magnetically different, then the molecule is said to have fluxionality nature. In this case, the signals corresponding to interchanged two or more groups will be identical, if the rate of exchange of the groups occurs very quickly. The fluxionality in organic molecules can be easily followed by multinuclear NMR spectroscopy.