What are the products, and their relative ratios, resulting from the ozonolysis of \(\beta\) -carotene? (Assume reductive workup.)

To determine the products and their relative ratios, we first need to analyze the structure of β-carotene. β-carotene is an organic compound with a molecular formula of C40H56 and an unsaturated hydrocarbon, which means it has carbon-carbon double bonds in its structure. Its structure consists of a long conjugated chain with alternating single and double bonds, terminated by isoprenoid groups on both ends.

Ozonolysis is a chemical reaction where ozone (O3) breaks the carbon-carbon double bonds in unsaturated hydrocarbons, such as β-carotene, to generate two new molecules. It is important to note that there are two types of workups for ozonolysis: reductive and oxidative. In this exercise, we are assuming a reductive workup by adding a reducing agent like dimethyl sulfide (DMS) after ozonolysis.

In the case of β-carotene, the central conjugated chain has a total of 11 carbon-carbon double bonds. All these double bonds will undergo ozonolysis, generating two new molecules (carbonyl-containing molecules) for each double bond. After the ozonolysis process, reductive workup will be performed to convert any intermediate ozonides into carbonyls.

After performing ozonolysis followed by reductive workup on β-carotene, the products obtained can be divided into two groups: 1. Aldehydes: At both the end of the β-carotene molecule, aldehyde groups are formed. 2. Ketones: The remaining double bonds within the chain will be cleaved, giving rise to ketone groups. Overall, from the ozonolysis of β-carotene, we will obtain the following products and their relative ratios: - 2 moles of 1,4-pentadienal (aldehyde): end groups for each β-carotene molecule. - 7 moles of acetone (ketone): from internal double bond cleavage. - 2 moles of isoprenoid-derived aldehyde Thus, the ratio of 1,4-pentadienal to acetone is 1:3.5 whereas the ratio of 1,4-pentadienal to isoprenoid-derived aldehyde is 1:1.