Enol dialkylphosphate

Fig. 17.73. Ketone —> alkane reduction via enol phospho-noamidates (for one way to prepare A, see Figure 13.24) and enol dialkylphosphates (one way to prepare B is to use a combination of the methods depicted in Figures 13.20 and 13.25). The cleavage of the Cjjj2—0 bond of the substrates occurs in analogy to the electron transfers in the formation of methylmagnesium iodide (Figure 17.44). The alkenyl-lithium intermediates are pro-tonated in the terminating step to afford the target alkenes.

The reduction of enol dialkylphosphate esters of ketones to alkenes has been known for some time recent work has now shown that the enolate oxygen atom in sterically unhindered enol diphenylphosphate esters can be replaced by an alkyl group using a lithium dialkylcuprate (Scheme 36), extending the scope of the reaction to a versatile synthesis of trisubstituted double bonds. 

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See also in sourсe #XX -- [ ]

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