Diels-Alder reaction

Diels-Alder reaction is a 100-year-old reaction that Diesl and Alder discovered. This powerful reaction won Novel prize in 1950 and is still widely used in synthetic labs. This jewelry represents a transition state of the four-carbon piece (left), combining with the two-carbon piece (right) to form a six-carbon ring. Although this 4+2 = 6 type reaction looks uncomplicated, the reaction proceeds well in reality only with careful substrate design. The one shown here is the almost perfect combination of reaction partners and gives a very clean reaction.