Editing Lactone (section)

==Synthesis==
[[File:Oxandrolones synthesis.svg|thumb|right|Oxandrolone synthesis]]

Many methods in ester synthesis can also be applied to that of lactones. Lactonization competes with [[polymerization]] for longer hydroxy acids, or the strained β{{nbh}}lactones. γ{{nbh}}Lactones, on the other hand, are so stable that 4-hydroxy acids (R-CH(OH)-(CH<sub>2</sub>)<sub>2</sub>-CO<sub>2</sub>H) spontaneously cyclize.

In one industrial synthesis of [[oxandrolone]] the key lactone-forming step is an [[organic reaction]] – esterification.<ref>''Development of a Commercial Process to Produce Oxandrolone'' John E. Cabaj, David Kairys, and Thomas R. Benson Org. Process Res. Dev.; '''2007'''; 11(3) pp 378–388; (Article) {{doi|10.1021/op060231b}}</ref><ref>The complete reaction sequence is [[bromination]] to a [[haloketone]] (not displayed), [[elimination reaction]] with [[lithium chloride]] to an [[enone]], [[organic oxidation]] by [[osmium tetroxide]] and [[lead tetraacetate]] with ring-opening and finally reduction of the [[aldehyde]] to the [[Alcohol (chemistry)|alcohol]] with [[sodium borohydride]] and intramolecular lactone formation</ref>

[[File:Iodolactonization.svg|thumb|right|iodolactonization]]
In [[halolactonization]], an [[alkene]] is attacked by a [[halogen]] via [[electrophilic addition]] with the cationic intermediate captured intramolecularly by an adjacent [[carboxylic acid]].<ref>[[Organic Syntheses]], Coll. Vol. 7, p.164 (1990); Vol. 64, p.175 ('''1986''') [http://orgsynth.org/orgsyn/pdfs/CV7P0164.pdf Article link]</ref>

Specific methods include [[Yamaguchi esterification]], [[Shiina macrolactonization]], [[Corey-Nicolaou macrolactonization]], [[Baeyer–Villiger oxidation]] and [[nucleophilic abstraction]].

[[File:γ-Lactones synthesis.svg|thumb|right|γ-Lactone synthesis from fatty alcohols and acrylic acid]]

An alternative radical reaction yielding γ-lactones is the [[manganese-mediated coupling reactions|manganese-mediated coupling]].