Chemistry

Catherine E. Housecroft, Edwin C. Constable

ISBN #9780273715450

4th Edition

995 Questions

13,222 Students Helped

Homework Questions

Summary

Learning Objectives

Key Concepts

Example Problems

Explanations

Common Mistakes

Summary

This chapter provides an extensive overview of alkenes and alkynes, covering their structure, bonding, and spectroscopic analysis. It delves into various synthetic routes and reaction mechanisms including electrophilic addition, radical reactions, polymerization, hydroboration, and isomerization processes. Additionally, it outlines the synthesis of alkynes and the importance of protective groups like Me3Si for terminal alkynes. The material emphasizes the practical applications of these reactions in organic synthesis and industrial chemistry, equipping students with both theoretical understanding and problem-solving skills.

Learning Objectives

Key Concepts

CONCEPT

DEFINITION

Acyclic and cyclic alkanes

A discussion of both open?chain (acyclic) and ring (cyclic) saturated hydrocarbons, emphasizing their structural features, nomenclature, conformational behavior (including ring strain and conformation), and the processes used in their interconversion and synthesis.

Example Problems

Example 1

Give systematic names to the following compounds: a.(FIGURE CAN'T COPY) b.(FIGURE CAN'T COPY) c.(FIGURE CAN'T COPY) d.(FIGURE CAN'T COPY) e.(FIGURE CAN'T COPY) f.(FIGURE CAN'T COPY)

Example 2

The IR spectrum of octa-I,7-diyne is shown in Figure $26.10 .$ Assign the adsorptions above $1800 \mathrm{cm}^{-1}$.

Example 3

How many signals would you expect to see in the proton decoupled $^{13}$ C NMR spectra of (a) penta-l,4-dicne and (b) penta-2,4-dicne? Could you distinguish the $(E)$ - and $(Z)$ -isomers of penta-2,4-diene using ' C NMR spectroscopy?

Example 4

(a) Two isomers of cyclooctadicne exhibit two and four signals respectively in their $^{13}$ C NMR spectra. Draw the structures of the isomers and assign one of the spectra to cach. (b) A third isomer of $\mathrm{C}_{8} \mathrm{H}_{12}$ has a bicyclic structure and its $^{13} \mathrm{C}$ NMR spectrum contains three signals. Suggest a structure for this isomer. Rationalize why the "H NMR spectrum of this compound has four signals.

Example 5

Draw the structure of hexa-l, 5 -diyne and interpret the following spectroscopic data. (a) The IR spectrum contains strong to medium absorptions at 3665,2922,2851 and $2123 \mathrm{cm}^{-1}$ in addition to bands in the fingerprint region. (b) The $^{13}$ C NMR spectrum has signals at $\delta 82.4,69.5$ and $18.6 \mathrm{ppm} .$ (c) The $^{1}$ H NMR spectrum has singlets at $\delta 2.06$ and 2.43 ppm.