This reaction is part of a much larger group of reactions, namely the 2 + 4 cycloadditions. The numbers 2 and 4 refer to the number of nonhydrogen atoms in the alkene and the diene, which form the ring. The term cyloaddition means that a ring is formed.
Otto Paul Hermann Diels[?] and Kurt Alder[?] got the Nobel Prize 1950.
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