Functional Phosphonium Salts

Two standard routes to y-functional phosphonium salts with electron-withdrawing groups consist in using the corresponding Michael alkenes to achieve either halide substitution in the -position to the functional group, in order to obtain y-functional vinylphosphonium salts, or Michael addition in the presence of acid to produce the y-functional alkylphosphonium salt (reaction 85). 

A number of other diaurated ylide derivatives have been obtained from the interaction of functionalized phosphonium salts such as [Ph3PCH2(C5H4N-2)]C104 with two equivalents of (triphenylphosphine)gold(I) acetylacetonate, which induce double deprotonation and subsequent auration of the methylene group (Scheme 2)150-152. 

In addition, LHMDS has been successfully used in the deprotonation of other functionalized phosphonium salts, such as oxazo-lidinone methyl 10 (eq 46), A(-methylfomiamide 11 (eq 47), and thiazolylmethyl 12 (eq 48). ... 

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