Conjugated Compounds and Ultraviolet Spectroscopy

Give IUPAC names for the following compounds:

Give IUPAC names for the following compounds:

Draw and name the six possible diene isomers of formula. Which of the six are conjugated dienes?

What product (s) would you expect to obtain from reaction of 1,3-cyclohexadiene with each of the following?

Electrophilic addition of to isoprene (2-methyl-1,3-butadiene) yields the following product mixture:  

Of the 1,2-addition products, explain why 3,4-dibromo-3-methyl-1-butene (21%) predominates over 3,4-dibromo-2-methyl-1-butene (3%).

Propose a structure for a conjugated diene that gives the same product from both 1,2 and 1,4-addition of HBr.

Draw the possible products resulting from addition of 1 equivalent of HCl to 1-phenyl-1,3-buta-di-ene. Which would you expect to predominate, and why?

Predict the products of the following Diels-Alder reaction:

Predict the products of the following Diels-Alder reaction:

(b) 

Di-tert-butyl-1,3-butadiene does not undergo Diels-Alder reactions. Explain.

Show the structure, including stereochemistry, of the product from the following Diels-Alder reaction:

Question: 1,3,5-Hexatriene has ${\lambda }_{max}$=258 nm. In light of your answer to Problem

14-48, approximately where would you expect 2,3-dimethyl-1,3,5-hexatriene to absorb?

Question: $\beta$Ocimene is a pleasant-smelling hydrocarbon found in the leaves of

certain herbs. It has the molecular formula and a UV absorption

maximum at 232 nm. On hydrogenation with a palladium catalyst,

2,6-dimethyloctane is obtained. Ozonolysis of $\beta$Ocimene, followed by

treatment with zinc and acetic acid, produces the following four

fragments:

(a) How many double bonds does $\beta$ocimene have?

(b) Is $\beta$ocimene conjugated or non-conjugated?

(c) Propose a structure for $\beta$ocimene.

(d) Write the reactions, showing starting material and products.