Organophosphorus reagents, Wittig reagent

Important and widely used variants of the Wittig reaction are based on carbanionic organophosphorus reagents, and are known as the Wadsworth-Emmons reaction, Wittig-Horner reaction or Horner-Wadsworth-Emmons reaction. As first reported by Horner, carbanionic phosphine oxides can be used today carbanions from alkyl phosphonates 13 are most often used. The latter are easily prepared by application of the Arbuzov reaction. The reactive carbanionic species—e.g. 14 —is generated by treatment of the appropriate phosphonate with base, e.g. with sodium hydride ... 

Abell, A. D. Edmonds, M. K. The Wittig and Related Reactions. In Organophosphorus Reagents Murphy, P. J., Ed. Oxford University Press Oxford, 2004 pp 99-127. 

Wittig reaction (Section 21.10) A reaction of a carbonyl group and an organophosphorus reagent that forms an alkene. 

Wittig reagent (Section 21.10A) An organophosphorus reagent having the general structure Ph3P=CR2. 

The Wittig reaction and its derivatives continue to find application in the synthesis of a diverse range of molecules. However, the aim of this chapter is to provide an overview of the literature published between July 2001 and June 2002 that concentrates on the chemistry of the organophosphorus reagents themselves, and so coverage of their synthetic applications is limited to a number of pertinent, illustrative examples. 

Gosney, I., Rowley, A. G. Transformations via phosphorus-stabilized anions. 1 Stereoselective syntheses of alkenes via the Wittig reaction. Organophosphorus Reagents Org. Synth. 1979,17-153. 

The Wittig reaction and its numerous derivations have undoubtedly proven to be one of the most useful and efficient methods for forming carbon-carbon double bonds . The reaction of an organophosphorus reagent with an aldehyde or ketone has also been frequently employed to extend simple dienals and dienones into more elaborate polyene systems. A key step in the convergent synthesis of the TB DMS-protected leukotriene A4 methyl ester, 19/ ,5 -Z-butyldimethylsiloxy-5S, 6S -epoxyeicosa-7 ,9 , 1IZ, 14Z-tetraenoate (43), was accomplished using a Wittig reaction between homoallylic phosphorus ylide 44 and Cl—Cll chiral epoxy dienal 45, derived from (—)-2-deoxy-D-ribose, shown in equation 29. ... 

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