Phospha- Peterson

Lithium mesityl(trimethylsilyl)phosphide was also used to introduce MesP=C(H)NMe2, by reaction with ALA-dimethyl form amide31. In the present chapter, we call reactions of this type the phospha -Peterson reactions. 

The scope and limitations of the base-catalysed Phospha-Peterson synthesis of phosphaalkenes of the type MesP=CRR (R,R = aryl), involving the reaction of MesP(SiMc3)2 and a carbonyl compound in the presence of a trace of KOH or NaOH, has been investigated and shown to provide a convenient and general route to these compounds in 40-70% yield, usually as a 1 1 mixture of E- and Z-isomers. A simple access to a series of l,l -ferrocenylenebis(dihalophosphines) has facilitated the synthesis of the first metaUocene-bridged bis(phosphaalkene)... 

Phosphaalkenes, phosphorus-carbon double-bond compounds, tvhich are usually unstable, can be synthesized by means of a Peterson-type reaction, the so-called phospha-Peterson reaction [415, 416]. One synthetic route to phosphaalkene 254 is by treatment of a lithium silylphosphide 253 bearing a bulky aryl substituent tvith an aldehyde, tvith elimination of a lithium silanolate (Scheme 2.155) [417, 418]. This reaction is found to be selective because of steric repulsion. Some ketones are also amenable to the phospha-Peterson reactions [419-422]. Phosphorus-containing cumulative double-bond compounds such as 1-phosphaallenes 255, 1,3-azaphosphaallenes 256, and 1,3-diphosphaallene 257 are also synthesized by vrray... 

Scheme 2.155. Synthesis of P=C double-bond compounds by the phospha-Peterson reaction.

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