A
transformation involving fusion of a new ring to a molecule via two new bonds. Some authors use
the term '
annelation' for the fusion of an additional ring to an already existing one, and '
annulation' for the formation of a ring from one or several acyclic precursors, but this distinction
is not made generally.
Source:
PAC, 1994, 66, 1077
(Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994))
on page 1083