Q17P - Organic Chemistry (Mcmurry)

Question

$\mathbf{\beta }$-Carotene, a yellow food-coloring agent and dietary source of vitamin A can be prepared by a double Wittig reaction between 2 equivalents of $\mathbf{\beta }$-ionylideneacetaldehyde and a diylide. Show the structure of the $\mathbf{\beta }$-carotene product.

Step-by-Step Solution

Answer

                                              Formation of -carotene

Step 1: Beta-carotene

$\mathbf{\beta }$-carotene is a precursor of vitamin A. In the human body, it is converted to vitamin A retinol. It is an organic compound that gives plants their color and belongs to the family of carotenoids.

Step 2: Formation of the desired product

When two equivalents of $\beta$-ionylideneacetaldehyde are reacted with a diylide, it gives a $\beta$-carotene which is represented as follows:

                                           Formation of $\beta$-carotene