88
Yohimbane (fundamental)
parent structure)
2.2.4
Subtractive Nomenclature
2 Substituted Systems
-:;/'
8
7
~ I I N4
1H
3
H
14
19
H;
16
2,3-Secoyohimbane
This nomenclature type uses substractive preftxes to indicate removal of
atoms or groups of atoms from a trivially or systematically named parent
structure. While additive nomenclature is used above all for hydrogenated
cyclic systems, subtractive nomenclature focuses primarily on the opposite phenomenon, i. e. introduction of unsaturation. This has already been
dealt with extensively in the discussions relating to hydrocarbon systems,
where the terminal syllables ... ene and ... yne signify loss of two and four
hydrogen atoms with concomitant formation of a double and triple bond,
respectively. A more explicit symbolization of dehydrogenation in the
guise of a subtractive preftx is particularly recommendable for certain
natural products of the steroid and carbohydrate series as well as for dehydroarenes (less precisely also named arynes) and dehydroannulenes.
H
HYrI HAY
H
1,2-Didehydrobenzene
(trivially = Benzyne,
Dehydrobenzene)
C =)
~
-
~
2,6-Didehydropyridine
(Pyridine- 2,6-diyl)
1,2,7,8-Tetradehydro [12] annulene