User:Benjah-bmm27/Oxaphosphetane

structure from M. Hamaguchi, Y. Iyamaa, E. Mochizukia, T. Oshimaa, Tetrahedron Lett. (2005) 46, 8949-8952
"First isolation and characterization of 1,2-oxaphosphetanes with three phenyl groups at the phosphorus atom in typical Wittig reaction using cyclopropylidenetriphenylphosphorane"

a rotatable, interactive Jmol model of this molecule is available at my website

Wikipedia coverage

• Wittig reaction
• Oxaphosphetane - I will write this soon

Basic description

An oxaphosphetane is a molecule containing a four-membered ring with one phosphorus, one oxygen and two carbon atoms. In a 1,2-oxaphosphetane phosphorus is bonded directly to oxygen. 1,2-Oxaphosphetanes are rarely isolated but are important intermediates in the Wittig reaction and related reactions such as the Seyferth–Gilbert homologation and the Horner–Wadsworth–Emmons reaction.

Similar molecules

• oxetane
• phosphetane
• 2,2-dihydro-1,2-oxaphosphetane (pentavalent P, parent of Wittig oxaphosphetanes)
• 1,2-oxaphosphetane (trivalent P)

Sources of information

VKA, JNH papers on Wittig mechanism

• J. Am. Chem. Soc., 2006, 128 (7), pp 2394–2409 (full details and discussion)
• J. Am. Chem. Soc., 2005, 127 (39), pp 13468–13469 (nice summary)

Journal articles

1. 1988: The stereochemistry of Wittig reactions of ylide-anions derived from semi-stabilized phosphonium ylides
2. 1989: Oxaphosphetane pseudorotation: rates and mechanistic significance in the Wittig reaction
3. 1994: Synthesis, Structure, and Thermolysis of a 1,5-Dioxa-4λ⁵-phosphaspiro[3.3]heptane: A Novel Pentacoordinate 1,2-Oxaphosphetane
4. 1995: Stereoselectivity in the Wittig Reaction of Aromatic Ketones: Origin of Preference for the Olefin Geometry
5. 1998: Observation of Pseudorotamers of Two Unconstrained Wittig Intermediates, (3RS,4SR)- and (3RS,4RS)-4-Cyclohexyl-2-ethyl-3,4-dimethyl-2,2-diphenyl-1,2λ⁵-oxaphosphetane, by Dynamic ³¹P NMR Spectroscopy: Line-Shape Analyses, Conformations, and Decomposition Kinetics
6. 2002: A Wittig Reaction with 2-Furyl Substituents at the Phosphorus Atom: Improved (Z) Selectivity and Isolation of a Stable Oxaphosphetane Intermediate
   (DOI = 10.1002/1099-0690(200204)2002:7<1143::AID-EJOC1143>3.0.CO;2-G)
7. 2002: First Isolation and Characterization of an Anti-Apicophilic Spirophosphorane Bearing an Oxaphosphetane Ring: A Model for the Possible Reactive Intermediate in the Wittig Reaction
8. 2003: Dilithiated phosphazenes: scaffolds for the synthesis of olefins through a new class of bicyclic 1,2-oxaphosphetanes
9. 2004: Molecular modeling of oxaphosphetane intermediates of wittig olefination reactions
10. 2007: New possible ionic structures in Wittig reaction: Analysis of stability and rotation barriers by semiempirical PM3 method
11. 2008: Dynamic NMR study of the oxaphosphetane complexation with lithium during the Wittig reaction

Websites

• http://www.organic-chemistry.org/namedreactions/wittig-reaction.shtm
• Alfa Aesar organophosphorus review
• http://www.springer.com/carey-sundberg/wadsworth_emmons/views/oxaphosphetane4a.html
• http://users.ox.ac.uk/~mwalter/web_05/resources/phos_chem/org_phosph_chem.shtml
• http://www.chm.bris.ac.uk/pt/harvey/postgradcc/exercises/wittig_exercise.htm – Professor Jeremy Harvey's Wittig modelling exercise