Functional chain creation from a phosphonium ylide

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). 

The Michael type of addition, in the presence of acids, has been extended successfully to cyclopropyl ketones347 (reaction 86). Of course, the functional group can also undergo subsequently a transformation202,346,347,349, compatible with the phosphonium structure (acetalization, thioacetalization, imination, etc.). 

---