spiro compounds
DESCRIPTION
probably one of my best ppt design. short presentation about spiro compounds.TRANSCRIPT
SPIRO COMPOUNDS
ORGANIC CHEMISTRY II
PLAN • Definition • Types • Nomenclature • Synthesis • Chirality • Uses
DEFINITION
A spiro compounds are bi- or polycyclic organic compounds with rings connected through just one atom. The rings can be different in nature or identical. The connecting atom is also called the spiroatom, most often a quaternary carbon ("spiro carbon")
TYPES There’s a mono- (2 rings) and poly- (3 or more) spiro compounds _________________________
NOMENCLATURE…
…eight?
by Adolf von Baeyer in 1900
PROPOSED
MONOSPIRO COMPOUNDS
All spiro compounds have the infix spiro followed by square brackets containing the number of atoms in the smaller ring and the number of atoms in the larger ring excluding the spiroatom itself; the numbers being separated by a dot.
A is called 1-bromo-3-
chlorospiro[4.5]decan-7-ol and compound
B is called 1-bromo-3-
chlorospiro[3.6]decan-7-ol.
POLYSPIRO COMPOUNDS
When naming polyspiro compounds, the prefixes di-, tri-, tetra-, etc. are first added to the front of the name to indicate the amount of spiroatoms, the single atoms between each ring. The atoms of the compound are numbered systematically. A polyspiro compound is numbered starting from a ring that holds one connecting spiroatom to another ring, i.e. a terminal ring; there can be two or more terminal rings to a polyspiro compound, so long as each of these rings has only one connecting spiroatom. In the terminal ring chosen to start the numbering, an atom of the ring next, and connected to the spiroatom, is labeled 1. Each following atom is numbered one higher than the previous - going around the compound.
dispiro [2.1.3.4] dodecan
SYNTHESIS
SYNTHESIS
We can obtain spiro compounds using intramolecular cyclization,
intra/intermolecular condensation
SYNTHESIS
Spiro compounds can also be obtained by regrouping another polycyclics
Heterocyclic spiro compounds are produced by the methods used in synthesis of simple heterocyclic compounds
SYNTHESIS
CHIRALITY
*term used to describing an object that is
non-superposable on its mirror image
*
CHIRALITY Some spiro
compounds exhibit axial chirality.
Spiroatoms can be centers of chirality
even when they lack the required four
different substituents normally observed in
chirality.
USES • Spiro compounds used as plasticizers (eg, glycerinacetal cyclic ketons), in perfumery, intermediate products in the synthesis of epoxy, in producing medicine. some spiro compounds are used as photochromic materials
• Spiro forms of lactones and oxazines are frequently used as leuco dyes, frequently displaying chromism - reversible change between their colorless and color form.
