Definition of "electrocyclic" []

• Describing a molecular rearrangement in which a covalent single bond is formed between the ends of a fully conjugated system resulting in a cyclic compound with one fewer double bonds (adjective)

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• "I began to look at all kinds of organic transformations, and so I was prepared when in the Spring of 1964 R.B. Woodward asked me some questions about what subsequently came to be called electrocyclic reactions."