1,5-Cyclooctadiene

COD reacts with borane to give 9-borabicyclo[3.3.1]nonane, commonly known as 9-BBN, a reagent in organic chemistry used in hydroborations:

:450px

COD adds {{chem2|SCl2}} (or similar reagents) to give 2,6-dichloro-9-thiabicyclo[3.3.1]nonane:

:File:CODSCl2.png

The resulting dichloride can be further modified as the diazide or dicyano derivative in a nucleophilic substitution aided by anchimeric assistance.

COD is used as an intermediate in one of the syntheses of disparlure, a gypsy moth pheromone.{{cite journal | doi = 10.1002/anie.197800471 | title = Synthesis of Disparlure by Kolbe Electrolysis | date = 1978 | last1 = Klünenberg | first1 = Helmut | last2 = Schäfer | first2 = Hans J. | journal = Angewandte Chemie International Edition in English | volume = 17 | pages = 47–48 }}

File:Ni(cod)2.png|Bis(cyclooctadiene)nickel(0).

File: Crabtree.svg|Crabtree's catalyst.

File: Cyclooctadiene-rhodium-chloride-dimer-2D-skeletal.png|The complex Cyclooctadiene rhodium chloride dimer.

File:Co(C8H12)(C8H13).png|Co(1,5-cyclooctadiene)(cyclooctenyl).

File:PdCl2(cod).png|Dichloro(1,5-cyclooctadiene)palladium

File:Ir2Cl2 cod 2improved.svg|cyclooctadiene iridium chloride dimer

File:Cl2Ptcod.png|Dichloro(1,5-cyclooctadiene)platinum

1,5-COD binds to low-valent metals via both alkene groups. Metal-COD complexes are attractive because they are sufficiently stable to be isolated, often being more robust than related ethylene complexes. The stability of COD complexes is attributable to the chelate effect. The COD ligands are easily displaced by other ligands, such as phosphines.

{{chem2|Ni(COD)2}} is prepared by reduction of anhydrous nickel acetylacetonate in the presence of the ligand, using triethylaluminium

:{{1/3}}{{chem2|[Ni(C5H7O2)2]3 + 2COD + 2Al(C2H5)3 → Ni(COD)2 + 2Al(C2H5)2(C5H7O2) + C2H4 + C2H6}}

The related {{chem2|Pt(COD)2}} is prepared by a more circuitous route involving the dilithium cyclooctatetraene:

:{{chem2|Li2C8H8 + PtCl2(COD) + 3C7H10 → [Pt(C7H10)3] + 2LiCl + C8H8 + C8H12}}

:{{chem2|Pt(C7H10)3 + 2COD → Pt(COD)2 + 3C7H10}}

Extensive work has been reported on complexes of COD, much of which has been described in volumes 25, 26, and 28 of Inorganic Syntheses. The platinum complex is a precursor to a 16-electron complex of ethylene:

:{{chem2|Pt(COD)2 + 3C2H4 → Pt(C2H4)3 + 2COD}}

COD complexes are useful as starting materials; one noteworthy example is the reaction:

:{{chem2|Ni(COD)2 + 4CO → Ni(CO)4 + 2COD}}

The product {{chem2|Ni(CO)4}} is highly toxic, thus it is advantageous to generate it in the reaction vessel upon demand. Other low-valent metal complexes of COD include cyclooctadiene rhodium chloride dimer, cyclooctadiene iridium chloride dimer, and {{chem2|Fe(COD)(CO)3}}, and Crabtree's catalyst.

The {{chem2|M(COD)2}} complexes with nickel, palladium, and platinum have tetrahedral geometry, whereas {{chem2|[M(COD)2]+}} complexes of rhodium and iridium are square planar.

:File:EE-COD synthesis.svg

The highly strained trans,trans isomer of 1,5-cyclooctadiene is a known compound. (E,E)-COD was first synthesized by George M. Whitesides and Arthur C. Cope in 1969 by photoisomerization of the cis,cis compound.{{cite journal | title = Irradiation of cis,cis-1,5-cyclooctadiene in the presence of copper(I) chloride | author1-link= George M. Whitesides|first1=George M.|last1=Whitesides | first2 = Gerald L.|last2= Goe | author3-link= Arthur C. Cope|first3=Arthur C.|last3=Cope | journal = J. Am. Chem. Soc. | year = 1969 | volume = 91 | issue = 10 | pages = 2608–2616 | doi = 10.1021/ja01038a036}} Another synthesis (double elimination reaction from a cyclooctane ring) was reported by Rolf Huisgen in 1987.{{cite journal | title = Preparation and conformation of (E,E)-1,5-cyclooctadiene | first1 = Dieter|last1= Boeckh | author2-link = Rolf Huisgen|first2=Rolf|last2=Huisgen | first3 = Heinrich |last3=Noeth | journal = J. Am. Chem. Soc. | year = 1987 | volume = 109 | issue = 4 | pages = 1248–1249 | doi = 10.1021/ja00238a046}} The molecular conformation of (E,E)-COD is twisted rather than chair-like. The compound has been investigated as a click chemistry mediator.{{cite journal | title = (E,E)-1,5-Cyclooctadiene: a small and fast click-chemistry multitalent | first1= Henning|last1= Stöckmann | first2 = André A.|last2= Neves | first3 = Henry A.|last3= Day | first4 = Shaun|last4= Stairs | first5 = Kevin M.|last5= Brindle | first6 = Finian J.|last6= Leeper | journal = Chem. Commun. | year = 2011 | volume= 47| issue= 25| pages= 7203–5| doi = 10.1039/C1CC12161H| pmid= 21611648}}

• Dibenzocyclooctatetraene

{{Reflist|30em|refs=

{{cite book | last1 = Buehler | first1 = C. | last2 = Pearson | first2 = D. | title = Survey of Organic Syntheses | url = https://archive.org/details/surveyoforganics00bueh | url-access = registration | publisher = Wiley-Interscience | location = New York | year = 1970}}

{{cite book | last1 = Shriver | first1 = D. | last2 = Atkins | first2 = P. | title = Inorganic Chemistry | url = https://archive.org/details/inorganicchemist00shri | url-access = registration | publisher = W. H. Freeman and Co. | location = New York | year = 1999 |isbn=978-0-716-72873-3}}

{{OrgSynth | collvol = 9 | collvolpages = 95 | year= 1998 | title = 9-Borabicyclo[3.3.1]nonane Dimer | first1 = John A. | last1 = Soderquist | first2 = Alvin | last2 = Negron | prep = cv9p0095}}

{{OrgSynth | first = Roger | last = Bishop | collvol = 9 | collvolpages = 692 | prep = CV9P0692| title = 9-Thiabicyclo[3.3.1]nonane-2,6-dione}}

{{cite journal | title = Mechanistic Insight Into High-Spin Iron(I)-Catalyzed Butadiene Dimerization | journal = Organometallics | year = 2016 | volume = 35 | pages = 2923–2929 | doi = 10.1021/acs.organomet.6b00474 | last1 = Lee | first1 = H | last2 = Campbell | first2 = M. G. | last3 = Sánchez| first3 = R. H. | last4 = Börgel | first4 = J. |last5 = Raynaud | first5 = J | last6 = Parker | first6 = S. E. | last7 = Ritter | first7 = T. | issue = 17}}

{{cite journal | title = 2,6-Dichloro-9-thiabicyclo[3.3.1]nonane: Multigram Display of Azide and Cyanide Components on a Versatile Scaffold | journal = Molecules | year = 2006 | volume = 11 | pages = 212–218 | url = http://www.mdpi.org/molecules/papers/11040212.pdf | doi = 10.3390/11040212 | last1 = Díaz | first1 = David | last2 = Converso | first2 = Antonella | last3 = Sharpless | first3 = K. Barry | last4 = Finn | first4 = M. G. | issue = 4| pmid = 17962753 | pmc = 6148556 | doi-access = free }}{{open access}}

{{cite book | last1 = Schunn | first1 = R. | last2 = Ittel | first2 = S. | title = Inorganic Syntheses | chapter = Bis(1,5-Cyclooctadiene)Nickel(0) | date = 2007 | volume = 28 | doi = 10.1002/9780470132593.ch25 | pages = 94–98 | isbn = 978-0-470-13259-3}}

{{Ullmann | first1 = Thomas | last1 = Schiffer | first2 = Georg | last2 = Oenbrink | title = Cyclododecatriene, Cyclooctadiene, and 4-Vinylcyclohexene | doi = 10.1002/14356007.a08_205.pub2 }}

{{cite book | last1 = Crascall | first1 = L | last2 = Spencer | first2 = J.| title = Inorganic Syntheses | chapter = Olefin Complexes of Platinum | doi = 10.1002/9780470132593.ch34 | volume = 28 | date = 2007 | pages = 126–132 | isbn = 978-0-470-13259-3}}

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{{cycloalkenes}}

{{DEFAULTSORT:Cyclooctadiene, 1,5-}}

Category:Cycloalkenes

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Category:Eight-membered rings

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