Cycloaddition Reactions - Multi-Step Synthesis

The diene shown on the left can be converted into the product shown by performing a simple [4+2] cycloaddition reaction, followed by a reaction of the cyclic alkene. For each problem, draw the structure of the diene and dienophile which would be required for the synthesis, the structure of the intermediate product, and the reaction conditions necessary to convert the intermediate into the final product.

Click the mouse on the buttons to view the synthetic logic, the structure of the intermediate and the solution to the problem.

The final product is an alkane and a cyclic ether with the oxygen bridging a six-membered ring. Since the oxygen is present in the starting diene, the double bond formed in the cycloaddition must have been reduced (H2/Pt) to give the alkane.








































This intermediate was formed from the starting diene and a dienophile.  To identify the reactants in a [4+2] cycloaddition reaction, identify the carbons of the dienophile (they will be the two carbons in a six-member ring which are opposite to the double bond in the product) and mentally split the bonds, separating the carbon skeletons of the diene and the dienophile. 































Furan undergoes [4+2] cycloaddition with ethene (ethylene) to give the bicyclic ether.  Reduction with H2/Pt gives the final product.